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The development of sustainable synthetic methods for converting alcohols to amines is of great interest due to their widespread use in pharmaceuticals and fine chemicals. In this work, we present an electrochemical approach by using green electrons for the selective oxidation of benzyl alcohol to benzaldehyde using a NiOOH catalyst, followed by its reductive amination to form benzyl-tert-butylamine. The number of Ni monolayer equivalents on the catalyst was found to significantly influence selectivity, with 2 monolayers achieving up to 90% faradaic efficiency (FE) for benzaldehyde in NaOH, while 10 monolayers performed best in a tert-butylamine solution (pH 11), yielding 100% FE for benzaldehyde. Reductive amination of benzaldehyde was optimized on Ag and Pb electrodes, with Ag achieving 39% FE towards the amine product, though hydrogen evolution remained a competing reaction. In situ FTIR spectroscopy confirmed the formation of benzaldehyde and its corresponding imine intermediate during oxidation, while reduction spectra supported the formation of the amine product. These results demonstrate the potential of paired electrolysis for alcohol-to-amine conversion, achieving an overall 35% FE for the synthesis of benzyl-tert-butylamine. This work paves the way for more efficient and sustainable electrochemical routes to amine synthesis. [ABSTRACT FROM AUTHOR]

The oxidative depolymerization of β-O-4 linkages into value-added aromatic chemicals is of great importance for lignin valorization. However, achieving highly selective and rapid cleavage of β-O-4 linkages under mild conditions remains a challenge. Herein, cobalt–cobalt oxides (Co-CoOx) supported on N-doped carbon (CoMA/C900) combined with a green and recyclable base K7HNb6O19 (KNb6) have shown remarkable activity for the one-step oxidative cleavage of lignin β-O-4 linkages. Under relatively mild conditions (100 °C, 0.2 MPa O2), a lignin β-O-4 alcohol model compound was almost completely converted within 3 h, affording a narrow product distribution of phenol (yield: 99%) and methyl benzoate (yield: 98%). Based on the control experiments, kinetic study, and spectroscopic analysis, a synergistic oxidative cleavage mechanism was proposed: CoMA/C900 activates molecular oxygen to form a superoxide radical, while basic KNb6 promotes deprotonation of secondary alcohol, and they synergistically catalyze the oxidation of β-O-4 alcohol and the rapid cleavage of Cβ–O and Cα–Cβ bonds. During the reaction, the oxidation of β-O-4 alcohol to β-O-4 ketone is the rate-determining step, while the cleavage of PP-one to phenol and methyl benzoate can be completed within 15 min. Moreover, the CoMA/C900–KNb6 catalyst is recyclable at least three times and highly active for the oxidative cleavages of other lignin models and organosolv birch lignin. [ABSTRACT FROM AUTHOR]

The document "Green Chemistry" published by the Royal Society of Chemistry in 2025 features cutting-edge research articles on various topics related to sustainable chemistry. The contents include critical reviews, tutorial reviews, communications, and papers covering a wide range of subjects such as catalytic hydrogenolysis of plastics waste, electrochemical synthesis methods, and green catalytic conversion processes. The journal aims to promote environmentally friendly practices and innovative solutions for a greener future. [Extracted from the article]

Organic electrochemical synthesis, a sustainable alternative to traditional organic synthesis, faces challenges in practical applications, such as limited current density, difficulty in recycling homogeneous electrochemical mediators, and large waste supporting electrolyte generation. In this work, we addressed these challenges by proposing a tandem electrochemical–chemical catalysis strategy, using selective alcohol electrooxidation to valuable aldehydes as a model transformation. Hypochlorite electro-generation and heterogeneous TEMPO-catalyzed alcohol oxidation were decoupled spatially, allowing each step to proceed independently under high rates and selectivity. Consequently, this strategy achieved industrially relevant current densities of 300–600 mA cm−2 with 64.7–81.8% faradaic efficiencies, resulting in a space–time yield (STY) of up to 516.95 kg (m3 h)−1 for benzaldehyde synthesis that significantly surpassed existing strategies. In addition, this strategy utilized the silica-supported TEMPO catalyst filled in a packed-bed reactor to achieve efficient single-pass conversion of alcohols to the corresponding aldehydes without the need for downstream catalyst separation, substantially reducing energy consumption for downstream separation. Furthermore, we developed a closed-loop tandem electrochemical–chemical catalysis system for gram-scale steroidal aldehyde synthesis, which incorporated an inline liquid–liquid separator for electrolyte recycling, thus significantly reducing the supporting electrolyte waste generation, which aligns with the principles of green chemistry and sustainable development. This work demonstrates a viable approach for the electrosynthesis of value-added organic intermediates under practical current densities with minimal waste electrolyte. [ABSTRACT FROM AUTHOR]

This study investigated the oxidation of 5-hydroxymethylfurfural (HMF) to produce valuable products such as 2,5-furandicarboxaldehyde (DFF), 5-formyl-2-furancarboxylic acid (FFCA) and 2,5-furandicarboxylic acid (FDCA) through (photo) chemical and enzymatic catalysis. Laccases from different sources, including Aspergillus spp., Pseudomonas cepacea, and Trametes versicolor, were evaluated for their catalytic activity in the HMF oxidation. Laccase from Trametes versicolor (LacTV) emerged as the most effective catalyst, achieving complete conversion of HMF under specific pH conditions. The reaction mechanisms were explored, revealing a preference for the primary alcohol oxidation pathway over the aldehyde, leading to the formation of DFF and subsequent conversion to FFCA and FDCA. The impact of substrate concentration on HMF conversion was examined, revealing optimal conversion at lower HMF concentrations (<100 mM) and reduced performance at higher concentrations (>100 mM). The study also examined the influence of blue light (430 nm) on this reaction, revealing the dependence on light exposure for gC3N4 based catalysts and a negative effect for LacTV. Furthermore, the study introduces a modular flow chemical platform that utilizes Continuous Stirred Tank Reactors (CSTR) in a cascade configuration, the optimization of HMF oxidation. The implementation of this innovative approach has led to the effective synthesis of FDCA, demonstrating an impressive 40-fold increase in productivity compared to the traditional batch system. These results present significant potential for advancing green chemistry and sustainable chemical synthesis, introducing novel possibilities for environmentally friendly HMF oxidation processes. [ABSTRACT FROM AUTHOR]

2,5-Furandicarboxylic acid (FDCA) is one of the most promising biodegradable substitutes for fossil-derived terephthalic acid (PTA) and adipic acid. The production of FDCA from biomass-derived 5-hydroxymethylfurfural (HMF) is significant and has attracted great attention. However, the major challenge lies in the development of a non-precious metal-based catalyst system without employing a homogeneous base. Herein, we successfully prepared an atomically dispersed Fe–N–C/γ-Al2O3 catalyst, which affords superior catalytic performance in terms of activity and stability with a FDCA yield of 99.8% and reusability of five recycle times in the catalytic oxidation of HMF to FDCA under base-free mild conditions. Based on controlled experiments and complementary characterization studies, we found that the atomically dispersed medium-spin Fe–N5 active sites together with the surface acidic/basic sites of alumina synergistically enhanced the catalytic activity and selectivity towards FDCA under base-free conditions. Our process eliminates the employment of expensive oxidants and corrosive bases, leading to economic and green biomass transformations. [ABSTRACT FROM AUTHOR]

Selective oxidation of alcohols to aldehydes/ketones is an important reaction in the fine and bulk chemicals fields. However, the classical alcohol oxidation methods are often performed under unfriendly conditions or use stoichiometric oxidants. Herein, we report an ingenious system that enables high selectivity (up to 99%) and high conversion (up to 97%) with high reaction rates in the aerobic oxidation of alcohols to aldehydes/ketones for a broad range of alcohols, proceeding smoothly via mixing the solvent ethyl acetate and HBr under ambient conditions with visible light irradiation. Experimental characterization and theoretical calculations reveal that solvated dispersion intermediates are formed spontaneously in situ through noncovalent interactions among the molecules in the reaction system, which is proposed to be the origin of the high selectivity and high activity of this reaction. The dispersion system provides a feasible activation approach for aerobic oxidation of alcohols to aldehydes/ketones with high performance under visible light. [ABSTRACT FROM AUTHOR]

Organic transformations via photocatalysis in water medium, especially for alcohol oxidation, are highly attractive but remain challenging. Herein, we report an efficient and green alcohol oxidation strategy in water medium using metal-cocatalyst-free colloidal CdS QDs as photocatalysts. The production rate of benzaldehyde in water medium reaches up to 24.8 mmol g−1 h−1, which is one order of magnitude higher than that in acetonitrile solvent. Interestingly, we found that the conversion of benzyl alcohol is markedly increased when we add water to pure acetonitrile solvent, implying that water has a positive effect on the oxidation of benzyl alcohol. Detailed experiments reveal that hydroxyl radicals, the dominant reactive oxygen species (ROS), are derived from superoxide radicals which are responsible for accelerating the production of benzaldehyde via a radical pathway. Additionally, the adsorption strength between benzyl alcohol and CdS QDs is further enhanced after the pre-adsorption of water on the CdS QD surface, contributing to more efficient charge transfer. The high selectivity is favored by the superior adsorption of the reactant alcohol and the rapid desorption of the desired product. This photocatalytic reaction is eco-friendly with 100% atom utilization. [ABSTRACT FROM AUTHOR]

The field of converting methane into valuable products using renewable energy sources under ambient conditions is both appealing and highly demanding. The inherent inertness of methane (CH4) necessitates the selective breaking of its first C–H bond while avoiding excessive oxidation, in order to transform CH4 into high-value products. Herein we present a novel approach for creating a highly concentrated Ni0/Ni2+-on-Cu interface using an O2 cold plasma in situ method to enhance the activity and stability of the CH4OR to low-carbon alcohol. The Cu@Ni–NiO electrocatalyst exhibits excellent performance for the CH4OR to low-carbon alcohol, showcasing a high faradaic efficiency (FE) of 86.7%, an impressive low-carbon alcohol yield of 1215.2 μmol g−1 h−1, remarkable durability (66 h) and a notable C2H5OH selectivity of 59.8% at 1.9 V vs. RHE. The ATRSEIRAS spectroscopy and DFT calculations further reveal that the synergistic effect of the Ni0/Ni2+-on-Cu interface can enhance the *O and *CH2 generation on Ni0, and the *CH2 spillover from Ni0 to Ni2+ atoms can also improve the C–C coupling reaction. Additionally, the in situ treatment with O2 cold plasma can enhance the formation of NiO, leading to a high concentration of the Ni0/Ni2+-on-Cu interface, which effectively prevents the oxidation of Ni0 during the CH4OR process. Furthermore, we developed a general oxidation strategy for the direct synthesis of transition metal nitrides by O2 cold plasma treatment of Ni0. Compared with the previous methods used for the preparation of NiO, the Ni-based metal oxide synthesis method offers several advantages, including simplicity and practicality, low cost, high throughput, pollution-free nature, low energy consumption and the capability to prepare metal oxides with controllable coordination number of the O atom. This work provides new insights into the highly efficient CH4OR process and presents an innovative, cost-effective method for preparing electrocatalysts. [ABSTRACT FROM AUTHOR]

The selective oxidation of alcohols has drawn significant attention in heterogeneous catalysis with the increasing use of Pickering interfacial catalysis (PIC) for green transformations of alcohols. However, it is still highly desirable to design and develop a solid catalyst with easy separation and recycling, made from abundant resources through a simple synthesis route, for the selective oxidation of alcohols. In this study, ferrite nanoparticles, synthesized via a hydrothermal process, were employed to act as a stabilizer and catalyst in PIC for the oxidation of benzyl alcohol using H2O2. The ferrite nanoparticles exhibited higher catalytic performance in PIC than in acetonitrile. The turnover number (TON) of the nanocatalyst in PIC was found to be 1.5–4 times higher than that in acetonitrile, and the reaction constant in PIC (kPIC = 0.712 h−1) was almost twice that in acetonitrile (kCH3CN = 0.310 h−1) for MnFe2O4 nanoparticles. Moreover, other alcohols could also be oxidized with moderately high conversion and selectivity in PIC. Significantly, the ferrite nanocatalyst could be easily separated from PIC using a magnet for reuse, achieving 88% BzOH conversion after five cycles. The use of hazardous organic solvents was avoided in PIC, making it a more advanced, green and sustainable reaction system. [ABSTRACT FROM AUTHOR]

The drawbacks commonly observed in synthetic methods for alcohol oxidation often stem from the utilization of complex, toxic, hazardous, or waste-producing oxidants. When sensitive or complex substrates bearing several functional groups are to be transformed, the selectivity of oxidation becomes another significant challenge. Herein, a chemoselective and operationally simple catalyst-free and additive-free method is presented for the aerial oxidation of 1-phenylpropargyl and 1-phenylallyl alcohols to their corresponding ketones, requiring only a solvent and visible light irradiation. The crucial role of dimethylsulfoxide (DMSO) as the solvent lies in achieving high chemoselectivity. Singlet oxygen, whose formation is photosensitized by the substrate and the product, is captured by DMSO, thereby preventing the undesired over-oxidation that occurs in other solvents. The application of DMSO to protect the substrate against singlet oxygen represents a novel approach that is potentially applicable to other aerobic photocatalytic processes. [ABSTRACT FROM AUTHOR]

The development of highly active and selective photocatalytic systems for the oxidation of benzylic C(sp3)–H and C(sp3)–OH to C＝O bonds under solvent-free conditions with molecular oxygen as an oxidant is attractive and challenging. In this study, a carbon- and PdO-doped Nb2O5-based catalyst (PdO/C–Nb2O5) was designed and synthesized. This photocatalyst showed excellent solvent-free aerobic photocatalytic performances for two typical oxidation reactions of benzylic C(sp3)–H and C(sp3)–OH to C＝O compounds. It was found that the doping of carbon and PdO in Nb2O5 can modify its surface electrons, increase oxygen vacancies, and change the positions of its valence band and conduction band. Besides, the kinetic study showed that the oxidation of C–H in ethylbenzene to C–OH is the rate-limiting step in the two-step oxidation of ethylbenzene to acetophenone. Moreover, a photocatalytic reaction mechanism was proposed based on these experiments. In addition, the solvent-free aerobic photocatalytic oxidation system showed a good substrate tolerance for benzylic C(sp3)–H and C(sp3)–OH compounds with different substituents to the corresponding ketones and aldehydes. [ABSTRACT FROM AUTHOR]

We have developed a practical KOtBu- or KOH-catalyzed aerobic cross-dehydrogenative coupling of benzylic C(sp3)–H bonds with various alcohols utilizing molecular oxygen as the sole oxidant. This transition-metal-free and chemical-oxidant-free methodology could enable direct and selective alkoxylation of benzylic C(sp3)–H bonds, especially the primary benzylic C–H bond, which is prone to undergo overoxidation. Moreover, the aerobic oxidative C–H/O–H cross-coupling approach provides a practical and sustainable pathway to construct benzyl ethers with high chemoselectivity under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Formic acid (FA) is a bulk chemical and a promising hydrogen energy carrier. The development of FA production from renewable biomass instead of multiple-step production from diminishing fossil resources is attractive. Formaldehyde (FAld) is another bulk chemical but industrial production requires high temperatures (250–600 °C). Herein, efficient oxidation of biomass to FA coupled with low-energy FAld production was developed using heteropoly acids as catalysts. Biomass and derivatives were oxidized to FA in yields of up to 88.6% while methanol was selectively oxidized to FAld at 90–190 °C with a markedly enhanced reaction rate. The synergistic mechanism has been unveiled that biomass activates methanol oxidation by boosting the catalytic redox cycle to form hydroxyl radicals and methanol scavenges the hydroxyl radicals to inhibit the overoxidation of biomass. This work opens up a promising direction for efficient FA production from biomass coupled with low-energy oxidation of alcohols to aldehydes. [ABSTRACT FROM AUTHOR]

The development of photocatalysts that are effective in different organic processes is a topic of great interest to researchers in materials chemistry. Herein, we report the design and synthesis of a new covalent triazine framework (CTF) built by acid-catalyzed trimerization of 4,4′-(benzo[b]benzo[4,5]thieno[2,3-d]thiophene-2,7-diyl)dibenzonitrile activated by microwaves that generates a new organic polymer, DPhBTBT-CTF. This CTF exhibits visible-light absorption due to the electron-donating BTBT units and the extended π-conjugated framework with the electron-acceptor triazine node and proves to be an efficient and versatile metal-free heterogeneous photocatalyst for different organic processes such as selective oxidations of both sulfides and benzyl alcohols to sulfoxides and benzaldehydes, respectively or the oxidative bromination of electron rich aromatic compounds. Moreover, two different proof of concept reactions were tested: the Diels–Alder cycloaddition and the hydroxylation of boronic acids. Heterogeneity studies confirmed that this photocatalyst can be recycled without significant loss of selectivity, and also some mechanistic tests suggested the preferred oxidation pathway. [ABSTRACT FROM AUTHOR]

Novel synthetic strategies for the production of high-value chemicals based on the 12 principles of green chemistry are highly desired. Herein, we present a proof of concept for two novel chemo-enzymatic one-pot cascades allowing for the production of valuable fragrance and flavor aldehydes. We utilized renewable phenylpropenes, such as eugenol from cloves or estragole from estragon, as starting materials. For the first strategy, Pd-catalyzed isomerization of the allylic double bond and subsequent enzyme-mediated (aromatic dioxygenase, ADO) alkene cleavage were performed to obtain the desired aldehydes. In the second route, the double bond was oxidized to the corresponding ketone via a copper-free Wacker oxidation protocol followed by enzymatic Baeyer–Villiger oxidation (phenylacetone monooxygenase from Thermobifida fusca), esterase-mediated (esterase from Pseudomonas fluorescens, PfeI) hydrolysis and subsequent oxidation of the primary alcohol (alcohol dehydrogenase from Pseudomonas putida, AlkJ) to the respective aldehyde products. Eight different phenylpropene derivatives were subjected to these reaction sequences, allowing for the synthesis of seven aldehydes in up to 55% yield after 4 reaction steps (86% for each step). [ABSTRACT FROM AUTHOR]

The aerobic oxidation of C(sp3)–H bonds is an important issue in organic synthesis, and hydrogen atom transfer (HAT) is an effective process to initiate the oxidation reaction. Here, we demonstrate an innovative strategy for the oxidation of C(sp3)–H bonds based on γ-valerolactone, which can be produced from biomass. This reaction system promotes the aerobic oxidation of various benzylic and allylic C(sp3)–H bonds and alcohols. Excellent chemoselectivity for 1-isochromanone was achieved with the assistance of Ni2Al-layered double hydroxide by increasing the difference in bond dissociation energy between the 1- and 4-C–H bonds of isochroman. The excellent application potential of the reaction system has been demonstrated via the synthesis of pharmaceutical molecules, modification of steroidal substrates, scaled-up oxidation experiments, and the ready availability of γ-valerolactone from biomass. This work also reports on a new carbon-centered radical for the activation of C(sp3)–H bonds. [ABSTRACT FROM AUTHOR]

In this article, an electricity-driven radical–polar crossover process for the (homo)cross-1,4-alkoxydimerization of alkenes is described. A variety of abundant and readily available (hetero)aryl alkenes and (halo)aliphatic alcohols can be used in the reaction to produce 1,4-dialkoxybutane derivatives in moderate to excellent yields. Alcohols serve as solvents and nucleophiles, participating in the reaction under mild and environmentally friendly conditions without the need for metals or oxidants. The reaction exhibits broad functional group tolerance and high product diversity. The only by-product of the reaction is hydrogen gas released at the cathode, making the method clean and highly atom-economical. The insensitivity to air enables this synthetic strategy to be efficient and convenient for the construction of various 1,4-dialkoxybutane derivatives. A gram-scale electrochemical experiment further demonstrated the synthetic utility of the method. [ABSTRACT FROM AUTHOR]

Both polyoxometalates (POMs) and organic small molecular catalysts show excellent performance in chemical synthesis. The incorporation of nanoscale POMs and organocatalysts allows the full expression of their respective merits and enables elusive reactions to be achieved in one catalytic system. However, the covalent combination of such two components has been rarely explored. Here, we have successfully designed and synthesized a bifunctional nanomolecular catalyst L -Pro-Mn-Anderson by grafting L -proline onto an Mn-Anderson POM for the first time, and catalytic experiments show that L -Pro-Mn-Anderson can realize the one-pot alcohol oxidation/three-component reaction to synthesize two types of heterocyclic compounds (5-aryl-pyrimido[4,5-b]quinoline-dione derivatives and pyrazolo[3,4-b] pyridine derivatives) in high yields up to 97%. The detailed characterization of the catalyst and the catalytic mechanism has shown that L -Pro-Mn-Anderson exhibits synergistic effects that combine both organic and inorganic catalytic functions, and the covalent linkage improves the overall redox activity of the molecular catalyst. This study opens up a new way for the design and application of covalently combined organic–inorganic molecular catalysts toward de novo organic synthesis. [ABSTRACT FROM AUTHOR]

The use of molecular oxygen is unquestionably the green path to the selective oxidation of alcohols to aldehyde and ketones. However, this reaction class poses safety problems associated with mixing oxygen with organic substrates. Continuous membrane reactors offer an attractive solution, owing to their ability to keep the oxygen phase separated from the liquid substrate, while controlling the dosing of oxygen during reaction. In this work, we demonstrate a slurry loop membrane reactor for continuous oxidations as well as hydrogenations. The catalyst slurry was circulated around a loop, to which a saturator containing a flat Teflon AF-2400 membrane was connected, along with a crossflow filter to keep the catalyst particles within the loop. Under a recycle flowrate 100 times higher than the inlet, the residence time distribution was found to be comparable to that of an ideal CSTR. A remarkably high kLa of 1.2 s−1 was achieved under a moderate specific power input of 2.4 kW m−3 during styrene hydrogenation. Continuous aerobic oxidations of various primary and secondary alcohols were carried out for 6–7 h at 90–120 °C and 2–6 bar, using a 1 wt% Au-Pd/TiO2 powder catalyst, leading to conversions between 17% and 75%. The reactor could also be operated in batch mode, achieving higher conversions, while scaled-up operations produced aldehyde yields of 0.4–19 g with only 88 mg of catalyst. Overall, the slurry loop membrane reactor provides significant advantages in terms of catalyst usage and process safety for aerobic oxidations. [ABSTRACT FROM AUTHOR]

In the pharmaceutical industry, the development of a safe, cost effective, productive, and sustainable process remains an exciting challenge that has to be solved to minimize the negative environmental impact caused by the huge quantity of reagents/solvents used. In this context, alcohol oxidation is probably one of the most challenging reactions, due to the inherent toxicity and the disposal issues associated with most of the available oxidants on the market. Herein, we describe our efforts to replace the use of toxic and expensive stoichiometric DDQ in the oxidation of a benzylic primary alcohol 2 in the phase II Servier clinical candidate S44819 manufacturing route. Screening of commonly used oxidants led to the identification and development of a highly efficient, selective and ecocompatible aerobic copper/TEMPO catalytic system, demonstrated by the improvement of green chemistry/sustainability metrics and reagents' cost from the original to the newly developed process. Gas–liquid mass transfer, safety assessment related to the use of air in a batch reactor and calorimetric analysis are discussed and this highly atom economical and low-cost aerobic oxidation was safely implemented at the pilot scale, enabling the manufacture of 13.3 kg of high-quality key intermediate 1. [ABSTRACT FROM AUTHOR]

Nitriles are versatile nitrogen-containing scaffolds that exist widely in medicines, dyes and functional materials, and are typically synthesized over homogeneous catalysts under relatively harsh conditions. Herein, through mimicking the key active species of hemoglobin p450 heme monooxygenase in most organisms, a Fe–N4 single atom-doped sulfur-containing carbon nitride (Fe/CNS) photocatalyst was facilely prepared by one-step thermal polymerization, which was illustrated to be efficient for renewable conversion of bio-based alcohols and NH2OH·HCl to a wide range of nitriles (80–92% yields) via cascade oxidation–ammoxidation at room temperature, or to quantitatively furnish benzaldehyde via oxidation in the absence of a nitrogen source. Theoretical calculations showed that the isolated Fe–N4 sites directly capture photogenerated electrons (e−) and molecular oxygen (O2) to generate superoxide radicals (˙O2−), while the surrounding S atoms confine photogenerated holes (h+). The high efficiency of Fe/CNS in the photo-generation of ˙O2− and holes may contribute to the smooth formation of nitriles by cascade photocatalytic oxidation of alcohol and ammoxidation via an in situ formed oxime, respectively. Moreover, Fe/CNS was also applicable to the selective synthesis of various imines (83–98% yields) from the oxidation of benzylamines or heterocyclic amines under visible-light irradiation, and could be recycled at least 5 times with no evident decline in catalytic activity. The strategy of rationally constructing atomic sites to spatially isolate paired electron–holes and form specific reactive species for enhanced photocatalytic activity/selectivity provides an efficient and green approach for biomass valorization. [ABSTRACT FROM AUTHOR]

Oxidation of fatty alcohols is an important reaction to produce industry-needed compounds such as fatty aldehydes and fatty acids. While electrochemical oxidation of alcohols in water represents an environmentally friendly approach, it is a great challenge for the oxidation of long-chain fatty alcohols because of their low reactivity and water-solubility. Here, a typical nitroxide radical, 2,2,6,6-tetramethylpiperidyl-1-oxy (i.e., TEMPO), functionalised surfactants have been developed and used as efficient catalysts for the electrochemical oxidation of long-chain fatty alcohols to fatty aldehydes and fatty acids. The surfactants with varying aliphatic chain-length (i.e., C4-NO˙ to C14-NO˙) increase the partition of fatty alcohols in water through the formation of co-micelles. This process enables the TEMPO-mediated electrocatalytic oxidation of fatty alcohols in water with an increased turnover frequency (TOF) and a 102–103 fold increase in the apparent reaction rate kobs compared with non-surfactant TEMPO derivative 4-acetamido-TEMPO (ACT). Bulk oxidation showed the electrocatalytic reaction cascade of fatty alcohols to corresponding fatty aldehydes and eventually to fatty acids, with conversions as high as 93%. [ABSTRACT FROM AUTHOR]

The selective halogenation of the inert C–C bonds of alcohol-based feedstock is of tremendous significance in synthetic chemistry. Previous halogenation usually requires a metal catalyst and/or an oxidant and is limited to the cleavage of the C–C bonds of tertiary cycloalkanols. Herein, we report a broadly applicable strategy for the synthesis of iodoalkanes, bromoalkanes and chloroalkanes via the halogen-bond-assisted C–C activation of cyclic and acyclic alkanols in the absence of catalysts and oxidants, where the inexpensive N-haloimides act as bifunctional reagents to activate and halogenate alcohols. This redox-neutral protocol is a general method for the halogenation of the C–C bonds of primary, secondary, and tertiary alkanols, thus installing three types of halogen atoms and boronic esters through one-pot deiodination–borylation in a wide range of feedstock chemicals in a practical and sustainable fashion. [ABSTRACT FROM AUTHOR]

This study developed a novel photocatalytic method to synthesize pyranones from furfural alcohols. By using 0.2 mol% equivalent of tris-Ir(ppy)3 as a photocatalyst under visible light and O2 as the reaction atmosphere, furfural alcohols were rapidly oxidized and hydrolyzed in the aqueous reaction solution to produce diol intermediates, which further underwent hydrolysis, furan ring-opening and rearrangement to form the final product pyranones. The entire reaction was carried out at room temperature with a yield as high as 86% and a conversion efficiency of 90%. This method is general and suitable for furfural alcohols with different substituted groups on the 5- and α-OH sites. We used in situ IR and real-time NMR to examine the reaction kinetics, GC-MS and isotope-labeling experiments to track the source of atom transfer in the reaction, and EPR to identify the singlet oxygen. The results showed that the reaction followed a first-order rate equation, and O2 oxidation was the rate-determining step. The transferred H atom came from the H2O solvent, the O atom from the O2 atmosphere, and the singlet oxygen from the O2 photocatalysis. The UV-vis and cyclic voltammetry results indicated that this photocatalysis reaction involved a single electron transformation process. We also used DFT calculation to simulate the reaction routes and showed that the tris-Ir(ppy)3 photocatalysis O2 oxidation in the aqueous phase was the critical step of endoperoxide oxidation, which differs from oxygen onium ion oxidation in the classic Achmatowicz rearrangement reaction. Our method can carry out a 10.0 gram-scale reaction with a 78% yield. It avoids stoichiometric consumption of toxic or corrosive oxidative reagents in the Achmatowicz rearrangement reaction. It may provide a novel, efficient, and "green" alternative to the Achmatowicz rearrangement reaction. [ABSTRACT FROM AUTHOR]

Aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is a promising alternative route to produce renewable biodegradable plastics, which has stimulated intense interest in recent years. Supported gold catalysts have shown great potential for this reaction, but the selectivity and stability need to be improved. In addition, the requirement for base additives makes the process less effective and sustainable. Herein, highly active and selective Au–Ag bimetallic nanoclusters supported on MgAl-hydrotalcite (HT) were developed for HMF oxidation to FDCA under base-free reaction conditions using molecular oxygen as the oxidant. The presence of small amounts of Ag (0.034–0.065 wt%) in Au25 clusters greatly enhanced the catalytic reaction rates and selectivity for HMF tandem oxidative steps, leading to both high conversion of HMF (>97%) and high yield of FDCA (>95%). Besides, the catalyst stability was also enhanced by the addition of Ag. The characterization results suggested that the substitution of Ag atoms modified the electronic structure of Au while likely maintaining the primary geometry. Thus, a significant synergistic effect could be observed over trace Ag modified Au–Ag bimetallic nanoclusters. The present work provides new insight into the alloying effect, and helps understand highly efficient Au-based catalysts for aerobic oxidation of biomass derived molecules under base-free conditions. [ABSTRACT FROM AUTHOR]

An efficient electrochemical Minisci reaction to access 3-hydroxyalkylquinoxalin-2(1H)-ones involving hydrogen-atom transfer (HAT) driven α-C(sp3)–H functionalization of alcohols was achieved. Transition metal- and chemical oxidant-free conditions were the attractive synthetic features. The hydrogen atom transfer agent was hydrazoic acid generated from TMSN3 in this transformation. Primary or secondary alcohols and a wide range of quinoxalinones were found to be compatible, providing the corresponding 3-hydroxyalkylquinoxalin-2(1H)-ones in good yields. [ABSTRACT FROM AUTHOR]

It is attractive but challenging to develop a non-noble metal-based photocatalytic system for the selective oxidation of benzyl alcohol to benzaldehyde under solvent-free conditions. Herein, a Z-scheme heterojunction photocatalyst of ZnO/C3N4 was designed and prepared. Under solvent-free irradiation conditions, benzyl alcohol can be exclusively oxidized to benzaldehyde with a yield of 99.8% and a formation rate of 16 633 μmol g−1 h−1 at room temperature. To the best of our understanding, the photocatalytic activity and selectivity of this oxidation process are much better than those reported for noble and non-noble metal-based photocatalyses. The water generated in the solvent-free oxidation process is revealed to disfavor the activity and selectivity. In addition, the mechanism of the title reaction is proposed. The present solvent-free photocatalytic system can be applied for the oxidation of benzylic, allylic, heterocyclic, and aliphatic alcohols to their corresponding aldehydes. [ABSTRACT FROM AUTHOR]

It is attractive but challenging to develop a non-noble metal-based photocatalytic system for the selective oxidation of benzyl alcohol to benzaldehyde under solvent-free conditions. Herein, a Z-scheme heterojunction photocatalyst of ZnO/C3N4 was designed and prepared. Under solvent-free irradiation conditions, benzyl alcohol can be exclusively oxidized to benzaldehyde with a yield of 99.8% and a formation rate of 16 633 μmol g−1 h−1 at room temperature. To the best of our understanding, the photocatalytic activity and selectivity of this oxidation process are much better than those reported for noble and non-noble metal-based photocatalyses. The water generated in the solvent-free oxidation process is revealed to disfavor the activity and selectivity. In addition, the mechanism of the title reaction is proposed. The present solvent-free photocatalytic system can be applied for the oxidation of benzylic, allylic, heterocyclic, and aliphatic alcohols to their corresponding aldehydes. [ABSTRACT FROM AUTHOR]

Imines and secondary amines have attracted widespread attention in the fields of medicine owing to their unique unit structures and biological activities. However, the design of catalysts for the targeted syntheses of imines and secondary amines presents challenges due to the uncontrollable cascade reaction of nitrobenzene (NB) and benzaldehyde (BA). Herein, we report that carbon-coated Co and PtCo catalysts (Co/SiO2@CN and PtCo/SiO2@CN) realize the directional synthesis of imines and secondary amines under the same conditions, respectively, through the synergistic action of the active components. The superior catalytic performance benefited from the integrated geometric and electronic effects. Specifically, the uniformly coated nitrogen-doped carbon drives the adsorption ability of NB more strongly than BA and inhibits the formation of benzyl alcohol. For Co/SiO2@CN, Co–Nx and metallic Co synergistically promote the highly selective synthesis of imines with much higher conversion (97%) and selectivity (98%) than most Co-based catalysts at 60 °C. For PtCo/SiO2@CN, the electron transfer between Pt and Co promotes the hydrogen spillover ability and enables it to afford 100% BA conversion and 100% secondary amine selectivity, reaching the TOF value of 296 h−1. This synthesis strategy provides an advanced concept for designing chemoselective catalysts, which has important implications for both scientific research and industrial applications. [ABSTRACT FROM AUTHOR]

An FeIII-based metal–organic framework denoted as MIL-100(Fe) coated with cobalt–aluminium layered double hydroxide (CoAl-LDH) nanoplates has been synthesized. The structural information was obtained through powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), nitrogen sorption (BET and BJH), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM) and associated energy dispersive X-ray (EDX), transmission electron microscopy (TEM) and diffuse reflectance UV–Vis spectroscopy (UV–Vis DRS) techniques. Such characteristic methods indicate that the bonding between mesoporous CoAl-LDH nanosheets and open metal sites of metal–organic frameworks leads to non-covalent composite formation. Also, CoAl-LDH linkers add the feature of mesoporosity to MIL-100(Fe). Furthermore, the Fe–O bonds resulting from the coordination of surface –OH groups in the layered double hydroxide structure to FeIII atoms of the crystal create unique optical properties in the hybrid structure, enhancing its photoreactivity. On the other hand, the lack of pore volume changes and differences among the optical properties indicate a non-covalent composite formation between MIL-100 (Fe) and CoAl-LDH. The CoAl-LDH/MIL-100(Fe) as a photocatalyst showed noticeable photocatalytic performance as compared to its aerobic alcohol oxidation reaction components under visible light irradiation. Also, it is noteworthy that the type of product depends on the reaction conditions. The relevant tests were performed in terms of stability and reusability and showed high photocatalytic efficiency after being reused up to ten times. Additionally, the retrieved CoAl-LDH/Fe-MOF nanocomposite underwent FT-IR and PXRD analyses, which confirmed the stability of the catalyst during aerobic alcohol oxidation. [ABSTRACT FROM AUTHOR]

The direct catalytic oxidation of alcohols to carboxylic acids is very appealing, however, economic and environmentally friendly catalytic systems should be further explored from the aspect of less waste production and a convenient procedure. Herein, we display a structurally defined inorganic ligand-supported iron compound, (TBA)3[FeMo6O18(OH)6] (simplified as FeMo6), which could be used as a heterogeneous molecular catalyst in water for this conversion, with oxygen as the terminal oxidant and KCl as an additive. The oxidation of various alcohols (aromatic and aliphatic) could be achieved in almost all cases under mild conditions and provided the corresponding carboxylic acids in high yields, including some active molecular entities and natural molecules with carboxyl structures. Detailed studies showed that chloride ions could combine with the molecular catalyst FeMo6 to form a supramolecular aggregate FeMo6·Cl, which could effectively catalyze the reaction, relying on the synergistic effect of chloride ions and FeMo6. Control experiments, 1H NMR studies and density functional theory (DFT) calculations showed that the oxidation reaction might involve a free radical pathway. [ABSTRACT FROM AUTHOR]

The development of green and sustainable methods for the conversion of aldehydes to carboxylic acids is of high academic and industrial interest. We demonstrate herein a practical and efficient light-promoted oxidation of aldehydes, utilising atmospheric oxygen as the sole oxidant. The transformation is promoted by either sunlight or LED 370 nm irradiation, without the use of a catalyst. A solvent mixture of acetone and water proved to be the most effective solvent medium. A wide range of aliphatic or aromatic aldehydes were successfully employed, providing the corresponding carboxylic acids in high to excellent yields. A mechanism was proposed based on direct infusion-high resolution mass spectrometry (DI-HRMS) studies, suggesting a solvent-assisted oxidative transformation. The method is green, sustainable and operationally simple under very mild conditions. [ABSTRACT FROM AUTHOR]

In this work, a fast and self-propagated carbonization (SPC) method to prepare phosphorus-doped carbon (PDC) and hybrid materials is proposed. PdZr/PDC prepared by the SPC method has good catalytic performance for both partial oxidation of benzyl alcohol to benzaldehyde and partial hydrogenation of phenol to cyclohexanone. The method has some obvious advantages, such as being simple and clean, and can be used easily for the large-scale preparation of the materials. [ABSTRACT FROM AUTHOR]

Epoxide compounds are ultra-important intermediates for manufacturing a variety of chemical products, yet their industrial preparation still suffers from some non-negligible drawbacks. Herein, novel CoOx nanoparticles dispersed within internal channels of hierarchical silicalite-1 zeolite (CoOx/h-S-1) catalysts, for precisely controllable initiation and transfer of free radical oxygen species under mild conditions, were initially prepared via combining silane pore-expansion and metal chelation by N-containing ligands under hydrothermal crystallization conditions. By using multiple characterization methods, it has been confirmed that CoOx nanoparticles loaded within zeolite internal channels through Co–O–Si bonds are majorly with the chemical valence state of +2 and a tetrahedral coordination environment, especially low Co loading, favors a small CoOx nanoparticle size and a high Co–O–Si proportion. CoOx/h-S-1 shows promising catalytic activity and lifetime in aerobic co-oxidation of olefin and aldehyde with a broad substrate scope and with high selectivities of epoxide and carboxylic acid, respectively. Remarkably, it has been found that loaded CoOx nanoparticles play key roles in enhancing radical initiation and transformation and oxygen transfer of reactive oxygen species (ROS); thus the catalytic performance can be tuned by altering the properties of both the catalyst and substrates. Importantly, these radical processes are profoundly verified by the impact of catalyst properties on the cis–trans isomerism of epoxidized methyl oleate (EMO), radical inhibition experiments and radical trapping experiments with EPR spectroscopy analysis. Consequently, this work not only provides an efficient and green epoxidation route over robust catalysts with easily available O2 as the oxidant, but also systematically reveals the fundamental understanding of the rational design and construction of metal nanoparticles within hierarchical zeolite channels and the corresponding structure–activity relationship for ROS transformation, which benefits the further development of both the catalyst and process technology. [ABSTRACT FROM AUTHOR]

By combining the double identity of a redox center and a Lewis acid site of the pyridinium derivative, the first bifunctional small molecule photocatalyst has been developed for the one-pot tandem oxidation–acetalization reaction. A mechanism study reveals that pyridinium-mediated electron transfer and the photoactivation of molecular oxygen greatly facilitate the transformation of benzyl alcohols into the corresponding aldehydes, while the Lewis acid site of this bifunctional photocatalyst promotes a highly efficient acetalization reaction without any significant loss in activity after multiple reaction cycles, thus achieving the direct conversion of various alcohols into either cyclic or acyclic acetals in good yields under mild conditions without any additives. [ABSTRACT FROM AUTHOR]

Replacing sluggish oxygen evolution reaction (OER) with electrocatalytic alcohol oxidation to construct hybrid water electrolysis systems is more economically attractive than conventional water splitting. Meanwhile, the electrooxidation of benzyl alcohol is regarded as a green alternative for the conventional synthesis of benzoic acid under moderate conditions. Here, we report the nitrogen-doped nickel-molybdenum oxide (N–Mo–Ni/NF) loaded on Ni foam through a one-step hydrothermal method for the selective electrooxidation of benzyl alcohol to benzoic acid in alkaline electrolytes. The N–Mo–Ni/NF electrode shows intriguing electrocatalytic activity and stability at the anode and only requires a low potential of 1.338 V (vs. RHE) to achieve a current density of 100 mA cm−2 in a 0.1 M benzyl alcohol solution, which is 252 mV lower than that of water oxidation. In addition, a yield of 98.2% of benzoic acid has been obtained with high faradaic efficiency of 98.7%. This work provides a facile strategy to design advanced non-precious electrocatalysts for the oxidation of benzyl alcohol. [ABSTRACT FROM AUTHOR]

The need of sustainable development in the modern era has driven the transformation of biomass for the production of fine chemicals into a strong trend of research. The aerobic oxidation of lignin-derived monomeric phenolics for the synthesis of various value-added products has attracted significant attention of the scientific community. In particular, enormous research interest has been devoted to the aerobic oxidation of vanillyl alcohol to vanillin, which is an important aroma chemical with wide applications. Four copper(II) complexes were synthesized for this purpose. The coordination of the Schiff base ligand L1 containing pendant thioether arm with copper(II) perchlorate and copper(II) chloride yielded homoleptic complex 1a and dinuclear complex 2a, respectively. Similar coordination of the NNS amine ligand L2 with copper(II) perchlorate and copper(II) chloride resulted in the formation of homoleptic complex 1b and mononuclear complex 2b, respectively. All four air stable complexes were tested for the aerobic oxidation of vanillyl alcohol to vanillin at ambient conditions in the presence of a catalytic amount of the TEMPO radical. Mononuclear complex 2b displayed the best catalytic activity. Species 2b is highly selective for the conversion of vanillyl alcohol to vanillin in various green solvent mixtures. Catalyst 2b is highly recyclable and did not show any reduction of catalytic activity after three cycles. Finally, the green and sustainable credentials of various catalytic protocols under various reaction conditions were compared with the help of CHEM21 green metrics toolkit. A plausible catalytic pathway is proposed based on the published reports and experimental evidences. [ABSTRACT FROM AUTHOR]

In recent years, photoredox chemistry has been intensively investigated due to its sustainability and low energy-cost. Here, we propose a physicochemical concept – called {2-phases 2-reactions 1-catalyst} – to perform two chemical reactions simultaneously with only one catalyst using a liquid–liquid biphasic system. The well-known and commercially available α-Keggin polyoxometalate (POM), PW12O403−, was used as a photocatalyst for oxidizing a hydrophobic compound in an organic phase. The reduced POM, PW12O404−, being more hydrophilic, diffuses then in the aqueous phase where it reduces a hydrophilic compound. After this step, the re-oxidized POM migrates back to the organic phase closing the catalytic cycle. We applied this concept to several basic reactions: oxidations of organic compounds (e.g. alcohol to aldehyde), degradation of organic dyes, metal recovery by reduction of metal ions, and in situ metal–organic complexation reactions. This concept is proposed as a powerful, simple and sustainable tool to couple diverse photo-oxidation/reduction reactions. As an example, oxidative dye degradation/metal (silver) recovery were performed using this general methodology. The main advantage of the {2-phases 2-reactions 1-catalyst} concept is the economy of one reactor and one catalyst, including its self-regeneration by another useful reaction. [ABSTRACT FROM AUTHOR]

One of the ideal green esterification reactions is aerobic oxidative esterification using only a stoichiometric amount of different alcohols via intermolecular selective alcohol oxidation followed by hemiacetal formation by the addition of the other alcohol and hemiacetal oxidation to esters. However, oxalic acid diester synthesis via oxidative esterification has not been reported to date, possibly owing to the difficulty of selectivity control of intermolecular alcohol oxidation and the chelating effects of ethylene glycol-derived alcohols/hemiacetals on inhibiting oxidation catalysts. Herein, using a CuCl/tetramethylethylenediamine/1,5-dimethyl-9-azanoradamantane N-oxyl catalyst, we describe a highly efficient aerobic oxidative esterification reaction of ethylene glycol to various oxalic acid diesters via selective oxidation of ethylene glycol-derived alcohols/hemiacetals even in the presence of other aliphatic primary alcohols. Notably, the green reaction works well using an ideal stoichiometric ratio of ethylene glycol and primary/secondary alcohols. Thorough experimental investigation and theoretical calculations revealed that highly selective oxidative esterification is enabled by the preferential bidentate coordination of ethylene glycol-derived alcohols/hemiacetals to the Cu(II) species, followed by efficient two-electron/one-proton transfer. [ABSTRACT FROM AUTHOR]

Esters are an important class of chemicals in industry. Traditionally, ester production is a multi-step process involving the use of corrosive acids or acid derivatives (e.g. acid chloride, anhydride, etc.). Therefore, the development of a green synthetic protocol is highly desirable. This work reports the development of a metal–organic framework (MOF) supported tandem catalyst that can achieve direct alcohol to ester conversion (DAEC) using oxygen as the sole oxidizing agent under strictly solvent-free conditions. By incorporating Ru nanoparticles (NPs) along with a homogeneous Lewis acid catalyst, scandium triflate, into the nanocavities of a Zr MOF, MOF-808, the compound catalyst, Sc–Ru⊂MOF-808, can achieve aliphatic alcohol conversion up to 92% with ester selectivity up to 91%. A mechanistic study reveals a unique "via acetal" pathway in which the alcohol is first oxidized on Ru NPs and rapidly converted to an acetal on Sc(III) sites. Then, the acetal slowly decomposes to release an aldehyde in a controlled manner for subsequent oxidation and esterification to the ester product. To the best of our knowledge, this is the first example of DAEC of aliphatic alcohols under solvent-free conditions with high conversion and ester selectivity. [ABSTRACT FROM AUTHOR]

We herein report that MoS2 with oxygen-implanting modification (O-MoS2) can work as a multifunctional catalyst to achieve the one-pot quinoline synthesis from basic nitroarenes and aliphatic alcohols. Different from common knowledge that the application of MoS2-based catalysts and above quinoline synthesis need anaerobic conditions, we conduct the heterogeneous catalysis under an unusual air atmosphere. Catalyst characterization and experimental results indicate that the MoOx clusters implanted in the MoS2 skeleton, not the coordinatively unsaturated Mo sites (CUS Mo), dominate the generation of quinolines. By overturning the catalysis perception that O2 adsorption on MoSx can deactivate the MoS2-based catalysts using an efficient method for in situ healing of the MoOx structure in O-MoS2 and protecting the O-MoS2 catalyst by inhibiting unwanted MoOx elimination with extra H*, we innovatively introduce O2 into the quinoline synthesis. The robust O-MoS2 can be consecutively used ten times without regeneration and it offers 69–75% yields of 2-methylquinoline from nitrobenzene and ethanol. Furthermore, different from the traditional transfer hydrogenation–condensation mechanism, an integrated oxidation–transfer hydrogenation–cyclization mechanism is proposed over the O-MoS2 catalyst. [ABSTRACT FROM AUTHOR]

Pyrrole-proline diketopiperazine (DKP) acts as an efficient mediator for the reduction of dioxygen by Hantzsch ester under mild conditions to allow the aerobic metal-free epoxidation of electron-rich alkenes. Mechanistic crossovers are underlined, explaining the dual role of Hantzsch ester as a reductant/promoter of the DKP catalyst and a simultaneous competitor for the epoxidation of alkenes when HFIP is used as a solvent. Expansion of this protocol to the synthesis of allylic alcohols was achieved by adding a catalytic amount of selenium dioxide as an additive, revealing a superior method to the classical application of t-BuOOH as a selenium dioxide oxidant. [ABSTRACT FROM AUTHOR]

With the ever-increasing awareness of environmental problems, the use of a green reaction medium in chemical processes has become an urgent research topic for green and sustainable chemistry. Developing excellent catalytic systems to ensure highly efficient molecular transport processes in reaction systems is still a challenge. Here, we introduce a facile template-assisted atomic layer deposition method to assemble amphiphilic confined TiO2/Pt@CNT and hydrophilic confined TiO2/Pt@TiO2/CNT. For TiO2/Pt@CNT, the void space between the outer TiO2 nanotube and the inner CNT forms an amphiphilic nanochannel. For TiO2/Pt@TiO2/CNT, a TiO2 layer is additionally deposited on CNTs. Furthermore, amphiphilic confined TiO2@Pt/CNT and hydrophobic confined C@Pt/CNT with similar tube-in-tube structures are also prepared, and Pt nanoparticles are supported on CNTs. Compared with the hydrophilic/hydrophobic counterparts, amphiphilic confined nanocatalysts exhibit substantially enhanced performance in biphasic benzyl alcohol oxidation and phenol hydrogenation reactions. Detailed analyses reveal that the amphiphilic microenvironment in nanochannels simultaneously promotes the transport of biphasic reactants to Pt sites, and thus improves the catalytic performance. Our assembly strategy can be used to reveal the relationship between the wettability microenvironment and molecular transport in nanochannels, which provides guidance to develop high-performance catalysts for other reactions. [ABSTRACT FROM AUTHOR]

The development of a combination enzyme and organocatalyst for aqueous sequential organic transformation has great significance, in that it is not only environmentally friendly but also overcomes only a single methodological drawback, either in the chemical or biological process. Herein, through the utilization of the bulky steric hindrance of chiral proline derivatives, an integrated laccase and proline as a chemo-enzymatic co-catalyst system is developed. It enables an efficient oxidation/aldol enantioselective sequential reaction to be accomplished, overcoming the mutual deactivation issue. As we present in this study, this one-pot organic transformation, an initial laccase-mediated oxidation of arylbenzyl alcohols and cyclohexanol to form aldehydes and cyclohexanone, followed by a subsequent proline derivative-catalyzed aldol condensation of the in situ generated intermediates, provides various 1,2-diastereoisomeric chiral β-hydroxy ketones with acceptable yields and high enantio-/diastereoselectivities. [ABSTRACT FROM AUTHOR]

Porous transition metal hydroxide (M(OH)2, M = Ni or Co) nanosheet/Ni foam electrodes were prepared by a facile electrodeposition method. The catalytic activities of the as-prepared porous electrodes for the electrooxidation of benzyl alcohol were investigated in NaOH aqueous solution. It was found that the Ni(OH)2 nanosheet/Ni foam electrode exhibited a superior current density to the obtained Co(OH)2 nanosheet/Ni foam electrode for the electrooxidation of benzyl alcohol, in which the Ni(OH)2 nanosheet electrode required an extremely low potential of ∼1.33 V vs. RHE to achieve a current density of 100 mA cm−2. The results of the durability test revealed that it exhibited an outstanding stability for the electrooxidation of benzyl alcohol. Moreover, the electrooxidation of benzyl alcohol for the green synthesis of benzoic acid with the simultaneous generation of hydrogen could be easily implemented in a two-electrode configuration by using noble-metal-free catalysts. When benzyl alcohol was fully oxidized, the optimized selectivity of benzoic acid and the faradaic efficiency for the electrooxidation of BnOH could reach 96% and 95%, respectively. [ABSTRACT FROM AUTHOR]

Superamphiphilic carbon from sawdust was directly prepared in oxygen/argon. The C element is responsible for the hydrophobic nature and the O element in anhydride and carboxyl groups endows carbon with hydrophilicity. Furthermore, in the oxidation of benzyl alcohol, conversion and yield could reach 94% doubled those of blank experiments in Pickering emulsion due to superamphiphilicity of carbon. [ABSTRACT FROM AUTHOR]

Visible light-mediated selective and efficient oxidation of various primary/secondary benzyl alcohols to aldehydes/ketones and oxidative dehydrogenation (ODH) of partially saturated heterocycles using a scalable and reusable heterogeneous photoredox catalyst in aqueous medium are described. A systematic study led to a selective synthesis of aldehydes under an argon atmosphere while the ODH of partially saturated heterocycles under an oxygen atmosphere resulted in very good to excellent yields. The methodology is atom economical and exhibits excellent tolerance towards various functional groups, and broad substrate scope. Furthermore, a one-pot procedure was developed for the sequential oxidation of benzyl alcohols and heteroaryl carbinols followed by the Pictet–Spengler cyclization and then aromatization to obtain the β-carbolines in high isolated yields. This methodology was found to be suitable for scale up and reusability. To the best of our knowledge, this is the first report on the oxidation of structurally diverse aryl carbinols and ODH of partially saturated N-heterocycles using a recyclable and heterogeneous photoredox catalyst under environmentally friendly conditions. [ABSTRACT FROM AUTHOR]