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This dissertation deals in part I with the synthesis of cyclic organic carbonates from the most sustainable C1 building block: CO2. Part II deals with the synthesis of amidines from carbodiimides, the diimino derivatives of CO2, or from thioureas as more accessible substrates, respectively. Part I Aqueous two phase synthesis of cyclic carbonates from CO2 and epoxides The focus of this chapter was on the development of a multiple phase catalysis for the preparation of organic carbonates with water as sustainable solvent. The aim was to utilise the miscibility gap between water and most cyclic organic carbonates for an energy efficient catalyst recycling. Additionally, water acts as co-catalyst via hydrogen bonding to the epoxide. The developed water-soluble organocatalysts 9a-Br demonstrated a high productivity for the carboxylation of propylene oxide (94% yield, 95% selectivity) and butylene oxide (95% yield, 97% selectivity). Through modification of the catalyst into surfactant shighly hydrophobic epoxide could be used as substrates as well. The catalyst could be recycled multiple times through simple phase separation, though a slow decline in productivity was observed. However, it was demonstrated that the catalyst 9a Br can be regenerated in situ by addition of small quantities of aqueous HBr after each run. This is explained by replacing the bromide lost through the formation of bromohydrin as trace product. Synthesis of cyclic carbonates from olefines and H2O2 1,2 hexane carbonate was obtained in 22% yield from olefines, CO2 and H2O2 under solvent free conditions. Towards oxidation by H2O2 stable, but less nucleophilic anions NO3- and Cl- were used as nucleophilic carboxylation catalysts instead of oxidation sensitive bromide and iodide. Unfortunately, decomposition of the quaternary ammonium cation of the ionic catalysts inhibited the implementation of an efficient orthogonal tandem catalysis as one pot synthesis. Additionally, both reaction steps favour different temperatures. Organic superbases as catalysts for the coupling of CO2 and epoxides In this chapter carbodiphosphorane and phosphazenyl phosphine superbases have been used as organocatalysts for the carboxylation of epoxides for the first time. The C- and P-bases, provided by IGOR MARTIN and SEBASTIAN WAGNER, were highly active organocatalysts. Epichlorohydrin conversion ]80% with yields up to 99% at full selectivity were achieved with just 0.01-0.1 mol% and TONs up to 8600 . The catalysts were also robust and remained active after 8 h reaction time and in presence of moisture. The free C-and P-base as well as the corresponding CO2- or water-adduct can be used as precursor. Additionally, it was shown that a too strong nucleophilic character of the superbase catalysts leads to the undesired polymerisation of the epoxide. Investigation of the reaction mechanism revealed that, regardless of if the free base or the CO2-adduct is employed, the onium bicarbonate of the superbase is present at the end of the reaction. This suggests that the reaction proceeds via an onium bicarbonate formed in situ from the superbase, CO2 and traces of moisture as catalytically active species. Preparation of carbodiimides from thioureas Diisopropyl carbodiimide was prepared from diisopropyl thiourea via dehydrodesulfurisation with strong bases and thiophilic metal cations as sulfur acceptors. The thiophilicity of the metal and the strength of the base impact the yield of the reaction. However, the concept could not be transferred to a wider selection of thioureas or ureas. The isolation of unstable primary alkyl substituted carbodiimides was not feasible. One pot synthesis of amidines from thioureas In 2 position alkyl, aryl or alkinyl substituted amidines were prepared from dialkyl and diaryl thioureas with MeLi, nBuLi, PhC≡CLi or PhLi. The desulfurisation does not require an additional sulfur acceptor next to the lithium cation itself. Through simple modification of the synthetic protocol, the method was extended to the synthesis of an unsymmetrical guanidine and a selection of 2-bis(amino)methylene nitriles. The required nucleophiles were prepared in situ by the same lithium base used for the deprotonation of the thiourea. This enables one pot conditions for these reactions. The isolation of carbodiimide intermediates is not necessary. This method allows the synthesis of several valuable compound classes from a single cheap, stable and accessible thiourea as starting material without the need for toxic metals.

Chiral benzothiazepines constitute the core structures of many foremost pharmaceuticals with diverse biological activities endowed by their unique scaffolds, which poses a great challenge to organic chemists and pharmaceutical researchers. This review provides a concise overview for the asymmetric synthesis of chiral benzothiazepine derivatives, focusing on advances in asymmetric catalysis, including metal catalysis, small-molecule organocatalysis and enzymatic catalysis. The catalytic asymmetric reactions, involving asymmetric epoxidation, reduction, dihydroxylation, hydrogenation, aldol reaction and other sulfa-Michael addition, have emerged as powerful strategies for the rapid construction of chiral benzothiazepine through single or multistep reactions. The booming asymmetric synthetic methodology affords us instructive clues for the highly efficient preparation of chiral benzothiazepines, facilitating their large-scale preparation and diversity-oriented synthesis.

This work introduces a new additive named 4,4’-trimethylenedipiperidine for the practical and ecofriendly preparation of ethyl 5-amino-7-(4-phenyl)-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylate derivatives. This chemical is commercially available and easy to handle. It also possesses a low melting point and a broad liquid range temperature, high thermal stability, and good solubility in water. Based on green chemistry principles, the reaction was performed in a) a mixture of green solvents i.e. water and ethanol (1:1 v/v) at reflux temperature, and b) the additive was liquefied at 65 ◦ C and the reaction was conducted in the liquid state of the additive. High yields of the desired triazolo-pyrimidines were obtained under both aforementioned conditions. Our results demonstrated that this additive, containing 2 Lewis base sites and able to act as an acceptor-donor hydrogen bonding group, is a novel and efficient alternative to piperidine, owing to its unique properties such as its reduced toxicity, nonflammable nature, nonvolatile state, broad liquid range temperature, high thermal stability, and ability to be safely handled. Furthermore, this additive could be completely recovered and exhibited high recyclability without any change in its chemical structure and no significant reduction in its activity. The current methodology has several advantages: (a) it avoids the use of hazardous materials, as well as toxic, volatile, and flammable solvents, (b) it does not entail tedious processes, harsh conditions, and the multistep preparation of catalysts, (c) it uses a metal-free and noncorrosive catalyst, and (d) reduces the generation of hazardous waste and simple work-up processes. The most important result of this study is that 4,4’-trimethylenedipiperidine can be a promising alternative for toxic, volatile, and flammable base reagents in organic synthesis owing to its unique properties.

Several N-isopropyliodobenzamides were evaluated as catalysts for the oxidation of benzhydrol to benzophenone in the presence of Oxone® (2KHSO5·KHSO4·K2SO4) as a co-oxidant at room temperature. A study on the substituent effect of the benzene ring of N-isopropyl-2-iodobenzamide on the oxidation revealed that its reactivity increased in the following order of substitution: 5-NO2 < 5-CO2Me, 3-OMe < 5-OAc < 5-Cl < H, 4-OMe < 5-Me < 5-OMe. The oxidation of various benzylic and aliphatic alcohols using a catalytic amount of the most reactive 5-methoxy derivative successfully resulted in moderate to excellent yields of the corresponding carbonyl compounds. The high reactivity of the 5-methoxy derivative at room temperature is a result of the rapid generation of the pentavalent species from the trivalent species during the reaction. 5-Methoxy-2-iodobenzamide would be an efficient and environmentally benign catalyst for the oxidation of alcohols, especially benzylic alcohols.

An iridium(III)-catalyzed three-component reaction of enamides, aryldiazonium tetrafluoroborates, and 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) (DABSO) for the direct C(sp )−H arylsulfonylation of enamides is developed. This transformation provides a robust and straightforward approach for preparing a diverse array of β-amidovinyl sulfones in moderate to excellent yields and high stereoselectivities without Light-emitting diode (LED) radiation. This transformation also features mild conditions, broad substrate scopes, and excellent functional group tolerance. We gratefully acknowledge the financial support from NanjingTech University (Start-up Grant No. 39837137, 39837101 and3827401739), and National Natural Science Foundation ofChina (21372210, 21672198, 21801129), the State Key Pro-gram of National Natural Science Foundation of China(21432009), Natural science research projects in Jiangsuhigher education institutions (18KJB150018) for generousfinancial support.

Local and catalytic acyl transfer for multipatterning of surfaces., Groundbreaking research done in the area of nanolithography makes it a versatile tool to produce nanopatterns for a broad range of chemical surface functionalization or physical modifications. We report for the first time an organocatalytic scanning probe nanolithography (o-cSPL) approach. Covalent binding of an organocatalyst on the apex of an atomic force microscope (AFM) tip gives way to a system that allows the formation of locally defined acylated-alcohol patterns on self-assembled monolayers (SAMs). With resolutions comparable to those of other cSPL methods, this first example of o-cSPL holds promise for future applications of bottom-up nanolithography set-ups employing this novel technique.

International audience; An efficient enantioselective Michael reaction of readily available α‐substituted N‐Boc isoxazolidin‐5‐ones is described under phase transfer conditions with up to 95:5 er. The organocatalytic process is promoted by a low catalytic loading of a commercially available N‐spiro quaternary ammonium salt. This sequence opens an entry to chiral heterocyclic platforms displaying a β‐amino carbonyl motif with an α‐all‐carbon quaternary stereogenic center. The methodology was also successfully extended to the asymmetric amination reaction using an azodicarboxylate electrophile.

Recently, organic catalysis has become a powerful alternative to the use of more traditional metal-based catalysts. In this study, 4-dimethylaminopyridine (DMAP), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) were applied to mediate the ring-opening graft polymerization (ROGP) of p-dioxanone (PDO) with xylan-based hemicelluloses in ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl). Excellent control of the molar ratio of the catalyst to anhydroxylose units (AXU) in xylan was found for a good tuning of the weight percent gain (WPG) of xylan-graft-poly(p-dioxanone) (xylan-g-PPDO) copolymers. As a result, the maximum WPG of xylan-g-PPDO copolymers was 431.07% (DMAP/AXU of 2/1), 316.72% (DBU/AXU of 0.2/1), and 323.15% (TBD/AXU of 0.2/1), respectively. The structure of xylan-g-PPDO copolymers was characterized with FT-IR and NMR. The thermal properties of copolymers were investigated using thermogravimetric analysis (TGA/DTG) and differential scanning calorimetry (DSC), and a significant difference was observed regarding the transition temperature (Tg), melting temperature (Tm), and crystallization temperature (Tc).

Multi-step processes catalysed by several catalysts working concurrently have been developed in nature, thus improving reaction efficiency. The quest for novel and improved catalytic systems has led to the development of biocatalytic and later to organocatalytic procedures as very valuable tools in asymmetric synthesis while using mild reaction conditions in the absence of metal catalysts. As a timeless challenge, chemists are facing the need for process designs in which different sorts of catalysts can operate successfully in a one-pot concurrent fashion. Likewise, such designs bring about the best of each catalyst and, in certain cases, enable us to improve problematic issues, such as reactivity, selectivity, solubility, inhibition, etc. Specifically, to combine these two types of catalysts in one-pot, achieving high yields and selectivity, is a fascinating aspect of catalysis. This review covers representative advances in this field, in particular those in which biocatalysts and organocatalysts are employed either in sequential reactions or in simultaneous processes. (Figure presented.). Fil: Bisogno, Fabricio Román. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina Fil: López Vidal, Martín Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina Fil: de Gonzalo, Gonzalo. Universidad de Sevilla; España

International audience; The efficient sulfinate‐catalyzed intermolecular addition reaction of α‐substituted allenyl sulfones and allenoates with Michael acceptors is highlighted. The sequence proceeds under mild conditions to provide a scalable and efficient access to versatile functionalized alkynes, displaying a quaternary stereocentre at the propargylic position. This work enriches the diversity of Lewis base organocatalysts in the field of allene chemistry, in addition to the well‐established phosphine and amine catalysts.

The asymmetric addition of malonates to in situ generated N-formylimines of aromatic aldehydes was achieved under phase-transfer catalysis using Cinchona alkaloids-derived quaternary ammonium salts. The resulting β-formamidomalonates have been efficiently converted into β-aryl-β-isocyano esters. Their utility in the multicomponent Ugi reaction with chiral cyclic imines has been demonstrated.

New materials for L-proline recycling have been developed. These materials have been applied to the L-proline-catalyzed aldol reaction between acetone and several aldehydes. The L-proline has been supported on the surface of modified silica gels with a monolayer of covalently attached ionic liquid with or without additional adsorbed ionic liquid. Good yields and ee values, comparable with those obtained under homogeneous conditions, have been obtained especially with imidazolinium-modified and 4-methylpyridinium-modified silica gels. Moreover, these materials have been easily recovered by simple filtration and studies about their reuse have been carried out. These studies showed that these materials can be used at least up to seven times. Finally, in the case of imidazolinium-modified silica gel, investigations showed that this support can be regenerated giving again a recyclable material with high isolated yields and reproducible ee values up to 13 cycles.

International audience; A simple and easily available organocatalytic system was developed for the polymerization of lactide. In partnership with tertiary amines, phenol derivatives were demonstrated to be excellent single H-bonding catalysts with high conversion within 24 h. In particular, ortho-, meta- and meta,meta'-trifluoromethylphenols revealed an amazing capacity for triggering the controlled ring opening polymerization (ROP) of lactide, through a fitted hydrogen-bond with the monomer.

An improved and greener approach towards the synthesis of glycerol carbonate, via transesterification, using 1-n-butyl-3-methylimidazolium-2-carboxylate as catalyst is described. The catalyst loading as low as 1% was sufficient to yield quantitative conversions. A plausible mechanism is proposed for the catalytic cycle leading to product formation.