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Herein, we disclose a highly efficient and facile electrochemical borylation of Morita–Baylis–Hillman adducts without using any metal catalyst. This methodology demonstrates excellent regio- and stereo-selectivity, leading to a wide range of functionalized E-allylic boronates, including derivatives of ibuprofen and menthol. Under mild and straightforward conditions, this redox-neutral reaction, combined with the scalability and synthetic applications of the allylic boronate esters, underscores its potential for a wide range of applications in organic synthesis. [ABSTRACT FROM AUTHOR]

Closo-Hexaborate (closo-B6H62−) can engage in nucleophilic substitution reactions with a wide variety of alkyl electrophiles. The resulting functionalized boron clusters undergo oxidative electrochemical deconstruction, selectively cleaving B–B bonds while preserving B–C bonds in these species. This approach allows the conversion of multinuclear boron clusters into single boron site organoboranes. Trapped boron-based fragments were isolated from the electrochemical cluster deconstruction process, providing further mechanistic insights into the developed reaction. [ABSTRACT FROM AUTHOR]

Hydrogels can form physically or chemically interactions with tissues and are widely used in the design of bioadhesive material. Polydopamine (PDA)/polyacrylamide (PAM)‐based adhesion hydrogels have emerged as one of the hydrogel adhesive materials with great potential for development. However, this type of hydrogel has low mechanical and adhesion properties, which has certain limitations in practical applications. Herein, inspired by the mussel adhesion mechanism, we introduced PDA into PAM/3‐aminophenylboronic acid grafted sodium alginate (SA‐PBA) double network system prepared a series of adhesive hydrogels, PDA was crosslinked by dynamic boronic ester bonds with SA‐PBA. The experimental results established that the hydrogels have favorable adhesive, anti‐fatigue, stretchable, and self‐healing properties. Cytocompatibility assay and in vitro hemolysis assay also indicated that the multifunctional hydrogel has excellent cytocompatibility and hemocompatibility. [ABSTRACT FROM AUTHOR]

Current routes to boronic acids and their corresponding esters to be used in subsequent Suzuki–Miyaura (SM) cross couplings impact the cost, waste, and safety concerns associated with generating these materials. A new method for installing the ethyl pinacol boronic ester, or B(Epin) derivative leads to stable borylated products under near-neat conditions using high concentrations of a green solvent and moderate reaction temperatures, catalyzed by relatively low palladium loadings. Alternatively, the newly fashioned Ar–B(Epin) can be generated in situ and used directly in the same pot for SM reactions leading to aromatic and heteroaromatic residues characteristic of the biaryl products being formed. An array of complex targets, including API-related products, can be generated via this green and environmentally responsible methodology. [ABSTRACT FROM AUTHOR]

Diabetic wounds often exhibit poor angiogenesis, infection, and prolonged inflammation, posing significant challenges for effective treatment. To address these issues, the thermoresponsive self-healing hydrogel dressings based on hydroxybutyl chitosan and 4-carboxyphenylboronic acid was developed for the delivery of curcumin. The hydrogel exhibited unique properties, including thermoresponsive sol–gel irreversibility, efficient self-healing, and pH/glucose responsive drug release. The irreversible gelation behavior was attributed to the formation of a strong dual crosslinking network involving hydrogen bonds and dynamic boronate ester interactions. Furthermore, the hydrogel dressings exhibited excellent self-healing properties and an injectable nature, making it suitable for in situ wound dressing applications. The pH/glucose dual-responsive release of curcumin was further verified, with accelerated release under acidic conditions and hyperglycemic environments, potentially benefiting diabetic wound treatment. The in vitro studies confirmed the hydrogel's antibacterial, antioxidant and anti-inflammatory activity and ability to promote cell migration and blood coagulation. The in vivo experiments further validate the hemostatic efficacy. This work presents a novel strategy for constructing self-healing, thermoresponsive hydrogel dressings with pH/glucose dual-responsive drug delivery capabilities for the effective management of chronic diabetic wounds. [ABSTRACT FROM AUTHOR]

Due to their remarkable features of lightweight, high strength, stiffness, high‐temperature resistance, and corrosion resistance, carbon fiber reinforced polymers (CFRPs) are extensively used in sports equipment, vehicles, aircraft, windmill blades, and other sectors. The urging need to develop a resource‐saving and environmentally responsible society requires the recycling of CFRPs. Traditional CFRPs, on the other hand, are difficult to recycle due to the permanent covalent crosslinking of polymer matrices. The combination of covalent adaptable networks (CANs) with carbon fibers (CFs) marks a new development path for closed‐loop recyclable CFRPs and polymer resins. In this review, we summarize the most recent developments of closed‐loop recyclable CFRPs from the unique paradigm of dynamic crosslinking polymers, CANs. These sophisticated materials with diverse functions, oriented towards CFs recycling and resin sustainability, are further categorized into several active domains of dynamic covalent bonds, including ester bonds, imine bonds, disulfide bonds, boronic ester bonds, and acetal linkages, etc. Finally, the possible strategies for the future design of recyclable CFPRs by combining dynamic covalent chemistry innovation with materials interface science are proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] Here, we report the preparation of a novel Janus nanoparticle with opposite Ir and mesoporous silica nanoparticles through a partial surface masking with toposelective modification method. This nanomaterial was employed to construct an enzyme-powered nanomachine with self-propulsion properties for on-command delivery. The cargo-loaded nanoparticle was provided with a pH-sensitive gate and unit control at the mesoporous face by first attaching boronic acid residues and further immobilization of glucose oxidase through reversible boronic acid esters with the carbohydrate residues of the glycoenzyme. Addition of glucose leads to the enzymatic production of H 2 O 2 and gluconic acid, being the first compound catalytically decomposed at the Ir nanoparticle face producing O 2 and causing the nanomachine propulsion. Gluconic acid leads to a pH reduction at the nanomachine microenvironment causing the disruption of the gating mechanism with the subsequent cargo release. This work demonstrates that enzyme-mediated self-propulsion improved release efficiency being this nanomotor successfully employed for the smart release of Doxorubicin in HeLa cancer cells. [ABSTRACT FROM AUTHOR]

Self‐adaptive hydrogels that can specifically respond to pathological cues and match the highly ordered tissue regeneration process are significantly on‐demand for effective wound management. Herein, multifunctional marine‐derived gold clusterzyme (AuNCs)‐based self‐adaptive hydrogels with microenvironment triggered release behavior are elaborately fabricated for on‐demand antioxidant, anti‐inflammatory and immunoregulation. The marine mussel‐derived catechol ligands (L‐3,4‐dihydroxyphenylalanine) endow AuNCs with enhanced superoxide dismutase‐mimic activity due to their high affinity to superoxide anion free radical (O2−•) and unique electron transfer mechanism, leading to 100% inhibition of O2−•. Upon uniformly crosslinking with phenylboronic acid‐modified marine‐derived sodium alginate (PBA‐Sa), the obtained AuNCs@PBA‐Sa hydrogels exhibit outstanding self‐healing property, tunable degradation and good removability. Meanwhile, AuNCs can greatly enhance the mechanical property and confer the hydrogel with favorable tissue adhesion for rapid hemostasis. Furthermore, injectable AuNCs@PBA‐Sa hydrogels can not only adapt their shape to the irregular wound, but also smartly adapt their microstructure to the physiological microenvironment of diabetic wound, leading to the responsive release of AuNCs upon the break of boronate ester bonds. The released gold clusterzymes can actively induce the generation of M2‐macrophage, demonstrating an outstanding anti‐inflammatory and pro‐regeneration effect. Therefore, the present multifunctional clusterzyme‐based self‐adaptive hydrogels hold great potential for remolding the dynamic tissue regeneration microenvironment and smart wound management. [ABSTRACT FROM AUTHOR]

Hydroalkylation of alkynes is a powerful method for alkene synthesis. However, regioselectivity has been difficult to achieve in transformations of internal alkynes hindering applications in the synthesis of trisubstituted alkenes. To overcome these limitations, we explored using boryl groups as versatile directing groups that can control the regioselectivity of the hydroalkylation and subsequently be replaced in a cross‐coupling reaction. The result of our exploration is a nickel‐catalyzed hydroalkylation of alkynyl boronamides that provides access to a wide range of trisubstituted alkenes with high regio‐ and diastereoselectivity. The reaction can be accomplished with a variety of coupling partners, including primary and secondary alkyl iodides, α‐bromo esters, α‐chloro phthalimides, and α‐chloro boronic esters. Preliminary studies of the reaction mechanism provide evidence for the hydrometalation mechanism and the formation of alkyl radical intermediates. [ABSTRACT FROM AUTHOR]

Non‐directed regioselective activation of bis(boronic esters), followed by functionalization, is reported. A bulky activator is shown to selectively activate the less hindered boronic ester enabling it to undergo stereospecific cross‐coupling to a variety of electrophiles. This steric‐based regioselectivity provides a simple and efficient method to prepare highly functionalized, enantiomerically enriched products starting from simple alkenes. [ABSTRACT FROM AUTHOR]

Comprehensive Summary Key Scientists Boronate esters are highly valued in synthetic and pharmaceutical industries for their versatility in creating C—C and C—X bonds. They also find applications as catalysts in chemical transformations as well as stimuli‐responsive materials in materials science. Some alkyl boronates themselves also show promising applications in medicinal chemistry. In the past few decades, chemists have been devoted to developing new methods or new starting materials for synthesizing boronate esters. Carboxylic acids and their derivatives are privileged chemical entities due to their readily availability or natural abundance, structural diversity, and chemical stability. Hence, the transformation of carboxylic acid and their derivatives to alkyl/aryl boronate esters has seen its fast development in the past decade. This review summarized the state‐to‐art development of decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives to aryl and alkyl boronate esters.The decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives started only in the past decade. In 2016, the decarbonylative borylation of carboxylic esters and amides was reported by Zhuangzhi Shi and Magnus Reuping's groups. Then, in 2017, studies on the decarboxylative borylation of redox‐active esters such as NHPI esters started to receive increasing attention by Aggarwal, Baran, Fu, Glorius, and Li's groups. From 2018 to 2023, large numbers of studies on the decarboxylative and decarbonylative borylation of carboxylic acids and their derivatives using transition‐metal‐catalyst, organo‐catalyst, or under photochemical or electrochemical conditions emerged. Due to space limitations, only pictures of scientists who have contributed more than two works in this area are shown herein. [ABSTRACT FROM AUTHOR]

Bis(alkenyl)boronates react with optically active Ir(π‐allyl) species in a process that involves allylation of the more substituted olefin and 1,2‐metalate shift of the less substituted olefin. The method constructs valuable enantioenriched tertiary allylic boronic esters with high chemoselectivity, enantioselectivity and diastereoselectivity. Allylic functionalization reactions transform the 1,3‐stereodiad to 1,5‐ and 1,6‐stereochemical relationships. [ABSTRACT FROM AUTHOR]

Teicoplanin has been banned in the veterinary field due to the drug resistance of antibiotics. However, teicoplanin residue from the antibiotic abuse of humans and animals poses a threat to people's health. Therefore, it is necessary to develop an efficient way for the highly accurate and reliable detection of teicoplanin from humans, food, and water. In this study, novel imprinted quantum dots of teicoplanin were prepared based on boronate affinity-based precisely controlled surface imprinting. The imprinting factor (IF) for teicoplanin was evaluated and reached a high value of 6.51. The results showed excellent sensitivity and selectivity towards teicoplanin. The relative fluorescence intensity was inversely proportional to the concentration of teicoplanin, in the range of 1.0–17 μM. And its limit of detection (LOD) was obtained as 0.714 μM. The fluorescence quenching process was mainly controlled by a static quenching mechanism via the non-radiative electron-transfer process between QDs and the five-membered cyclic boronate esters. The recoveries for the spiked urine, milk, and water samples ranged from 95.33 to 104.17%, 91.83 to 97.33, and 94.22 to 106.67%, respectively. [ABSTRACT FROM AUTHOR]

Complex dynamic systems displaying interdependency between nitroaldol and boronic ester reactions have been demonstrated. Nitroalkane‐1,3‐diols, generated by the nitroaldol reaction, were susceptible to ester formation with different boronic acids in aprotic solvents, whereas hydrolysis of the esters occurred in the presence of water. The boronic ester formation led to significant stabilization of the nitroaldol adducts under basic conditions. The use of bifunctional building blocks was furthermore established, allowing for main chain nitroaldol‐boronate dynamers as well as complex network dynamers with distinct topologies. The shape and rigidity of the resulting dynamers showed an apparent dependency on the configuration of the boronic acids. [ABSTRACT FROM AUTHOR]

Photoredox catalysis provides a green and sustainable alternative for C−H activation of organic molecules that eludes harsh conditions and use of transition metals. The photocatalytic C−N borylation and C−H arylation mostly depend on the ruthenium and iridium complexes or eosin Y and the use of porphyrin catalysts is still in infancy. A series of novel 21‐thiaporphyrins (A2B2 and A3B type) were synthesized having carbazole/phenothiazine moieties at their meso‐positions and screened as catalysts for C−N borylation and C−H arylation. This paper demonstrates the 21‐thiaporphyrin catalyzed C−N borylation and het‐arylation of anilines under visible light. The method utilizes only 0.1 mol % of 21‐thiaporphyrin catalyst under blue light for the direct C−N borylation and het‐arylation reactions. A variety of substituted anilines were used as source for expensive and unstable aryl diazonium salts in the reactions. The heterobiaryls and aryl boronic esters were obtained in decent yields (up to 88 %). Versatility of the 21‐thiaporphyrin catalyst was tested by thiolation and selenylation of anilines under similar conditions. Mechanistic insight was obtained from DFT studies, suggesting that 21‐thiaporphyrin undergo an oxidative quenching pathway. The photoredox process catalyzed by 21‐thiaporphyrins offers a mild, efficient and metal‐free alternative for the formation of C−C, C−S, and C−Se bonds in aryl compounds; it can also be extended to borylation reaction. [ABSTRACT FROM AUTHOR]

In this contribution, the transformation of polydicyclopentadiene (PDCPD) from thermoset into vitrimer is introduced. First, two N‐coordinated diboronic diols are successfully synthesized via the reaction of N,N,N‐tri(2‐hydroxyethyl)amine and/or N,N,N",N"‐tetrakis(2‐hydroxyethyl)ethylene diamine with 4‐(hydroxymethyl) phenylboronic acid and then they are transformed into two N‐coordinated cyclic boronic diacrylates. The latter two dienes carrying electron‐withdrawing substituents are used for the ring opening insertion metathesis copolymerization (ROIMP) of dicyclopentadiene to afford the crosslinked PDCPD. In the crosslinked PDCPD networks, N‐coordinated cyclic boronic ester bonds are integrated. It is found that the as‐obtained PDCPD networks displayed the excellent reprocessing properties. In the meantime, the fracture toughness is significantly improved. Owing to the inclusion of N‐coordinated cyclic boronic ester bonds, the modified PDCPDs have the thermal stability much superior to plain PDCPD. The results reported in this work demonstrate that PDCPD can successfully be transformed into the vitrimers via the introduction of N‐coordinated cyclic boronic ester bonds. [ABSTRACT FROM AUTHOR]

Despite the paramount importance of the Suzuki–Miyaura coupling (SMC) in academia and industry, and the great promise of iron to offer sustainable catalysis, iron‐catalyzed SMC involving sp3‐hybridized partners is still in its infancy. We herein report the development of a versatile, well‐defined electron‐deficient anilido‐aldimine iron(II) catalyst. This catalyst effectively performed C(sp3)−C(sp2) and C(sp3)−C(sp3) SMC of alkyl halide electrophiles and (hetero)aryl boronic ester and alkyl borane nucleophiles respectively, in the presence of a lithium amide base. These couplings operated under mild reaction conditions and displayed wide functional group compatibility including various medicinally relevant N‐, O‐ and S‐based heterocycles. They also tolerated primary, secondary and tertiary alkyl halides (Br, Cl, I), electron‐neutral, ‐rich and ‐poor boronic esters and primary and secondary alkyl boranes. Our methodology could be directly and efficiently applied to synthesize key intermediates relevant to pharmaceuticals and a potential drug candidate. For C(sp3)−C(sp2) couplings, radical probe experiments militated in favor of a carbon‐centered radical derived from the electrophile. At the same time, reactions run with a pre‐formed activated boron nucleophile coupled to competition experiments supported the involvement of neutral, rather than an anionic, (hetero)aryl boronic ester in the key transmetalation step. [ABSTRACT FROM AUTHOR]

Herein, we investigated hydrogels composed of boronic-acid-functionalized alginate and blended with polyvinyl alcohol (PVA) of different molecular weights to control the release of metoclopramide hydrochloride as a function of pH and shear stress. The functionalization of alginate introduced dynamic covalent bonding and pH-responsive properties that can modulate network connectivity. The study investigated the viscoelastic properties of the hydrogels, their drug release profiles, and their responsiveness to changes in pH and shear forces. The results showed that a higher PVA molecular weight and alkaline pH conditions increased hydrogel viscosity and stiffness due to a more stable and interconnected network structure than acidic pH. Metoclopramide release revealed that the hydrogels exhibited pH-responsive drug release behavior. The drug was more readily released under acidic conditions due to the instability of sp2-hybridized boronate ester bonds. The influence of shear forces on the release of metoclopramide was also investigated at shear rates of 1, 10, and 100 s−1, revealing their effect on matrix stiffening. Research shows that AlgBA/PVA hydrogels have unique properties, such as dynamic covalent bonding, that make them sensitive to external mechanical forces. This sensitivity makes them ideal for applications where physiological conditions trigger drug release. [ABSTRACT FROM AUTHOR]

The environmentally benign synthesis of indoline boronic esters, especially through a way of arylboration to alkenes, remains a challenge due to the use of transition metals or high-temperature conditions. We described a photoinduced metal-free arylboration of unactivated alkenes for the synthesis of indoline boronic esters and 1,2,3,4-tetrahydroquinoline boronic ester in good yields. This approach showed good compatibility and great efficiency for a range of allylphenylamines as well as alkylamine. Remarkably, this transformation also suggested that the base is not necessary for photosensitizer-free diboron reagent mediated mild generation of aryl radical. Furthermore, compared to previously reported methods, this approach is mild and environmentally benign. [ABSTRACT FROM AUTHOR]

A visible‐light‐induced method was developed to synthesize selenylated cyclic boronic esters through intermolecular oxyselenenylation. This method can be performed under additive‐free and photocatalyst‐free conditions and generates potentially pharmaceutically useful heterocycles. A plausible reaction mechanism was proposed based on several control experiments and previous reports. [ABSTRACT FROM AUTHOR]

Polymers are ideally utilized as damping materials due to the high internal friction of molecular chains, enabling effective suppression of vibrations and noises in various fields. Current strategies rely on broadening the glass transition region or introducing additional relaxation components to enhance the energy dissipation capacity of polymeric damping materials. However, it remains a significant challenge to achieve high damping efficiency through structural control while maintaining dynamic characteristics. In this work, we propose a new strategy to develop hyperbranched vitrimers (HBVs) containing dense pendant chains and loose dynamic crosslinked networks. A novel yet weak dynamic transesterification between the carboxyl and boronic acid ester was confirmed and used to prepare HBVs based on poly (hexyl methacrylate‐2‐(4‐ethenylphenyl)‐5,5‐dimethyl‐1,3,2‐dioxaborinane) P(HMA‐co‐ViCL) copolymers. The ABn ${{AB}_{n}}$ ‐type of macromonomers, the crosslinking points formed by the dynamic covalent connection via the associative exchange, and the weak yet dynamic exchange reaction are the three keys to developing high‐performance HBV damping materials. We found that P(HMA‐co‐ViCL) 20k‐40‐60 HBV exhibited ultrahigh energy‐dissipation performance over a broad frequency and temperature range, attributed to the synergistic effect of dense pendant chains and weak dynamic covalent crosslinks. This unique design concept will provide a general approach to developing advanced damping materials. [ABSTRACT FROM AUTHOR]

A series of tri-coordinated zinc alkyl complexes with the general molecular formula [κ2NE-{NHIRP(Ph)(E)N-Dipp}ZnEt] [R = Dipp (2,6-diisopropylphenyl), E = S (3a), Se (3b) and R = tBu (tert-butyl), E = S (4a), Se (4b)] bearing imino-phosphanamidinate chalcogenide ligands were prepared in good yields from the reaction between the protic imino-phosphanamidinate chalcogenide ligand [NHIRP(Ph)(E)NH-Dipp] [R = Dipp, E = S (1a), Se (1b) and R = tBu, E = S (2a), Se (2b)] and diethylzinc at room temperature. The molecular structures of all the zinc complexes were established by single-crystal X-ray diffraction analysis. In the solid state, all complexes exhibited a distorted trigonal planar geometry around the zinc ion. Metal-chalcogenide (Zn–S/Se) interactions were observed in the coordination sphere. These zinc alkyl complexes were employed as pre-catalysts in the hydroboration reaction of nitriles and esters to obtain the corresponding N,N-diborylamines and boronate esters, respectively, under ambient conditions. A wide substrate scope of nitriles and esters is presented. [ABSTRACT FROM AUTHOR]

The Zweifel olefination is a highly efficient and versatile method for constructing carbon-carbon double bonds in organic synthesis. It avoids the use of transition metals and has been applied in natural product synthesis and drug discovery. Recent progress in the field includes the use of new organometallic species, electrochemical and photocatalyzed reactions, and exploration of milder reaction conditions. However, further research is needed to develop less functional-group-sensitive reagents and investigate new strategies for generating alkenyl boron complexes. [Extracted from the article]

This article discusses the modular synthesis of conjugated aromatic boronate esters through radical xanthate addition. The researchers successfully synthesized xanthates with phenylboronate groups and demonstrated their potential for synthesizing boronate-containing conjugated aromatic compounds. The document provides detailed information about the synthesis and characterization of various compounds, including their chemical structures, spectroscopic data, and yields. It can be useful for researchers studying organic synthesis and compound characterization. [Extracted from the article]

Advancements in hydrogel bioadhesives for sealing gastrointestinal perforations (GP) face challenges due to weak mechanical properties, causing leakage, especially on uneven wound surfaces. Herein, a Janus hydrogel is introduced featuring a two‐step cross‐linking process, designed to serve as an efficient bioadhesive using a sprayable method. This Janus hydrogel formulation is achieved by modifying a photocurable hyaluronic acid hydrogel with dopamine (DA) and phenylboronic acid (PBA) groups, enabling reversible boronate ester bonds. These dynamic cross‐linking bonds facilitate shear‐thinning and self‐healing abilities, ensuring secure adhesion to complex wounds. A subsequent photocurable irreversible cross‐linking stage results in the formation of a hydrogel barrier with asymmetric adhesive properties, imparting inherent mechanical strength for postoperative anti‐adhesion. To enhance the clinical practicality of this hydrogel, an integrated sprayer device is further developed, enabling the efficient delivery of hydrogel at any angle and over long distances under minimally invasive conditions. Therefore, the HADP hydrogel, integrated with the sprayer device, successfully addressed the limitations associated with hydrogel bioadhesives in clinical applications concerning angles and terrains. This integrated approach presents a compelling solution for repairing gastrointestinal perforations in clinical settings. Moreover, it demonstrates significant potential for diverse applications in repairing complex wound surfaces. [ABSTRACT FROM AUTHOR]

The loss of function after prolonged periods of use is inevitable for all materials including plastics. Hence, self‐healing capabilities are a key development to prolong the service lifetime of materials. One of such self‐healing capabilities can be achieved by integrating dynamic bonds such as boronic ester linkages into polymeric materials, however the rate of self‐healing in these materials is insufficient and current methods to accelerate it are limited. In this study, we report the rational design, synthesis and characterization of a fluorinated elastomer (FBE15) that utilizes enhanced interaction between polymer chains afforded by strong dipole‐dipole interactions from −CF3, which showed a significant increase in binding energy to −7.71 Kcal/mol from −5.51 Kcal/mol, resulting in increased interaction between the boronic ester linkages and improving self‐healing capabilities of boronic ester materials, drastically reducing the time required for stress relaxation by 900 %. The bulk elastomer is capable of ultrafast self‐healing in a one‐click fashion that can happen in mere seconds, which can then be stretched to 150 % of its original length. By utilising the dynamic cross‐linking, FBE15 is also capable of both mechanical reprocessing into the same materials and chemical recycling into its starting materials, respectively, further allowing reconstruction of the elastomers that have comparable properties to the original ones at the end of its service lifespan. [ABSTRACT FROM AUTHOR]

Lipoxins are pro‐resolving mediators that play an important role in the resolution phase of the innate inflammatory response. However, because of their chemical and metabolic instability, the design of more stable synthetic analogues of lipoxin A4 and lipoxin B4 is an ongoing area of study. Herein we report the asymmetric synthesis of an aromatic lipoxin B4 analogue containing a conformationally rigid and potentially more metabolically resistant bicyclo[1.1.1]pentane (BCP) ring incorporated into the upper alkyl chain. This was achieved by the development of a 9‐step chiral‐pool synthesis of a novel BCP‐containing boronic ester coupling partner which could serve as a common precursor to the target analogue as well as other analogues with further modifications to the aromatic core. [ABSTRACT FROM AUTHOR]

Trialkyl phosphines PMe3 and PEt3 catalyze the 1,2‐cis‐diboration of 1,3‐butadiynes to give 1,2‐diboryl enynes. The products were utilized to synthesize 1,1,2,4‐tetraaryl enynes using a Suzuki‐Miyaura protocol and can readily undergo proto‐deborylation. [ABSTRACT FROM AUTHOR]

Silyl‐heterocycles offer a unique handle to expand and explore chemical space, reactivity, and functionality. The shortage of catalytic methods for the preparation of diverse and functionalized silyl‐heterocycles however limits widespread exploration and exploitation. Herein the borane‐catalyzed intramolecular 1,1‐carboboration of silyl‐alkynes has been developed for the synthesis of 2,3‐dihydrosilolyl and silylcyclobut‐2‐enyl boronic esters. Successful, catalytic carboboration has been achieved on a variety of functionally diverse silyl‐alkynes, using a borane catalyst and transborylation‐enabled turnover. Mechanistic studies, including 13C‐labelling, computational studies, and single‐turnover experiments, suggest a reaction pathway proceeding by 1,2‐hydroboration, 1,1‐carboboration, and transborylation to release the alkenyl boronic ester product and regenerate the borane catalyst. [ABSTRACT FROM AUTHOR]

Background: Signal transducer and activator of transcription 3 (STAT3) is a protein that regulates cell proliferation and differentiation, and it is attracting attention as a new index for evaluating cancer pathophysiology, as its activation has been highly correlated with the development and growth of tumors. With the development of STAT3 inhibitors, the demand for imaging probes will intensify. Noninvasive STAT3 imaging can help determine the cancer status and predict the efficacy of STAT3 inhibitors. In this study, we aimed to develop an imaging probe targeting STAT3 and synthesized [18F]FBNAF, which was derived from a STAT3-selective inhibitor as the lead compound, followed by in vitro and in vivo evaluations of [18F]FBNAF in positron emission tomography for STAT3. Results: The results revealed that FBNAF concentration-dependently inhibited STAT3 phosphorylation, similar to the lead compound, thereby supporting radiosynthesis. [18F]FBNAF was easily synthesized from the pinacol boronate ester precursor with suitable radiochemical conversion (46%), radiochemical yield (6.0%), and radiochemical purity (> 97%). [18F]FBNAF exhibited high stability in vitro and in vivo, and radioactivity accumulated in tumor tissues expressing STAT3 with an increasing tumor/blood ratio over time, peaking at 2.6 ± 0.8 at 120 min after injection in tumor-bearing mice. Tumor radioactivity was significantly reduced by the coinjection of a STAT3-selective inhibitor. Furthermore, the localization of radioactivity was almost consistent with STAT3 expression based on ex vivo autoradiography and immunohistochemistry using adjacent tumor sections. Conclusions: Thus, [18F]FBNAF could be the first promising STAT3-targeting probe for PET imaging. A STAT3 imaging probe provides meaningful information on STAT3-associated cancer conditions and in tumor microenvironment. [ABSTRACT FROM AUTHOR]

The defluoroborylation of fluoroarenes by chromium-catalyzed cleavage of unactivated C–F bonds is described. The reaction uses HBpin as the boron source, low-cost and commercially available chromium salt as the precatalyst, and terpyridine as a crucial ligand, providing a protocol with atom-efficient benefits and a wide range of applicable substrates for the functionalization of aryl C–F bonds. Preliminary mechanistic studies indicate that an unprecedented Cr-catalyzed magnesiation of the unactivated C–F bond occurred. The generated arylmagnesium intermediates then participated in the subsequent borylation reaction. The application of the strategy in the preparation of valuable derivatives is demonstrated by the late-stage functionalization of boronate ester groups. [ABSTRACT FROM AUTHOR]

Sustainable adhesives with simultaneous high strength and excellent ductility are important but still challenging. Here, an epoxy adhesive with simultaneously strong, tough, and sustainable features by designing a new hierarchical energy‐dissipated cross‐linking structure is reported: an annular structure containing quadruple internal B─N coordination boronic esters (AQBN). Under small strain, the AQBN structure is rigid to enhance the tensile strength of the adhesive. With medium strain applied, its non‐coplanar ring and internal quadruple B─N coordination can orderly open, providing mechanical energy dissipation and excellent ductility. Therefore, this multilevel structure can endow epoxy adhesives with both high strength and toughness. Besides, the rapid dynamic exchange and internal B─N coordination in boronic esters enable the adhesives to have good sustainability and environmental tolerance, respectively. As a result, the epoxy adhesives exhibit simultaneous high adhesive strength (18.5 MPa), outstanding toughness (work of debonding of 29692 N m−1), good chemical/physical recyclability, and excellent environmental reliability (humidity, water, high/ultralow temperature, and organic solvents). This work provides a new strategy for balancing the strength, toughness, and sustainability of adhesives. [ABSTRACT FROM AUTHOR]

The reversibility of the covalent interaction between boronic acids and 1,2- or 1,3-diols has put the spotlight on this reaction for its potential in the development of sensors and for the fishing of bioactive glycoconjugates. In this work, we describe the investigation of this reaction for the reversible functionalization of the surface of CdSe/ZnS Quantum Rods (QRs). With this in mind, we have designed a turn-off Förster resonance energy transfer (FRET) system that ensures monitoring the extent of the reaction between the phenyl boronic residue at the meso position of a BODIPY probe and the solvent-exposed 1,2-diols on QRs' surface. The reversibility of the corresponding boronate ester under oxidant conditions has also been assessed, thus envisioning the potential sensing ability of this system. [ABSTRACT FROM AUTHOR]

Boronate esters are a class of compounds containing a boron atom bonded to two oxygen atoms in an ester group, often being used as precursors in the synthesis of other materials. The characterization of the structure and properties of esters is usually carried out by UV-visible, infrared, and nuclear magnetic resonance (NMR) spectroscopic techniques. With the aim to better understand our experimental data, in this article, the density functional theory (DFT) is used to analyze the UV-visible and infrared spectra, as well as the isotropic shielding and chemical shifts of the hydrogen atoms 1H, carbon 13C and boron 11B in the compound 4-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)benzaldehyde. Furthermore, this study considers the change in its electronic and spectroscopic properties of this particular ester, when its boron atom is coordinated with a fluoride anion. The calculations were carried out using the LSDA and B3LYP functionals in Gaussian-16, and PBE in CASTEP. The results show that the B3LYP functional gives the best approximation to the experimental data. The formation of a coordinated covalent B–F bond highlights the remarkable sensitivity of the NMR chemical shifts of carbon, oxygen, and boron atoms and their surroundings. Furthermore, this bond also highlights the changes in the electron transitions bands n → π* and π → π* during the absorption and emission of a photon in the UV-vis, and in the stretching bands of the C=C bonds, and bending of BO2 in the infrared spectrum. This study not only contributes to the understanding of the properties of boronate esters but also provides important information on the interactions and responses optoelectronic of the compound when is bonded to a fluorine atom. [ABSTRACT FROM AUTHOR]

To date, it remains challenging to achieve a general and catalytic α‐arylation of cyclic 1,3‐dicarbonyls, particularly ubiquitous heteroaromatic ones. In most cases, the preparation of their medically significant arylated derivatives requires multistep synthetic sequences. Herein, we introduce a new, convenient strategy involving the conversion of cyclic 1,3‐dicarbonyls to cyclic iodonium ylides (CIYs), followed by rhodium‐catalyzed α‐arylation with arylboronic reagents via carbene coupling. This approach is mild, operationally simple, base‐free, biocompatible, and exhibits broad substrate scope (>100 examples), especially with respect to various heteroaromatic 1,3‐dicarbonyls and ortho‐substituted or base‐sensitive arylboronic acids. Importantly, owing to the excellent compatibility with various arylboronic acids or boronate esters (ArBpin, ArBneop, or ArBF3K), this method allows the late‐stage installation of heterocyclic 1,3‐dicarbonyl motifs in highly complex settings. The utility of this transformation is further demonstrated through significantly simplifying the synthesis of several bioactive molecules and natural products. [ABSTRACT FROM AUTHOR]

We report a Cu‐catalyzed oxidative coupling of aliphatic amines with benzylic and aliphatic boronic esters to give high value alkyl amines, products found widely in applications from medicinal chemistry to materials science. This operationally simple reaction, which can be performed on gram scale, runs under mild conditions and exhibits broad functional group tolerance. The terminal oxidant of the reaction is O2 from the air, avoiding the need for additional chemical oxidants. Investigation into the reaction mechanism suggests that the boronic ester is activated by an aminyl radical, formed through oxidation of the amine by the Cu catalyst, to give a key alkyl radical intermediate. To demonstrate its utility and potential for late‐stage functionalization, we showcase the method as the final step in the total synthesis of a TRPV1 antagonist. [ABSTRACT FROM AUTHOR]

Dynamic BO bonds are often applied to fabricate reversible‐cross‐linking and reprocessable polymer networks due to their high thermodynamic stability and kinetic tunability. However, it is still difficult to tailor boronic ester polymers, which have both excellent mechanical and self‐healing properties in the absence of external stimuli. To address the above challenge, a range of room‐temperature self‐healable vitrimers are prepared by the reactions of various poly(vinyl hydroxyalkyl ether‐alt‐dialkyl maleate) copolymers and 1,4‐phenyldiboronic acid. The dynamic cross‐linking networks offer the as‐prepared vitrimers superior mechanical properties and thermostability. Because of the presence of dynamic boronic ester bonds, the networks also demonstrated self‐healing (the tensile strength recovered to 83% after 3 days at room temperature) and reprocessing capabilities (no significant change in tensile strength after thrice process recycles). Moreover, the vitrimers have potential as promising damping materials with wide temperature windows around room temperature. For example, the vitrimer of poly(ethylene glycol monovinyl ether‐alt‐dibutyl maleate) and 1,4‐phenyldiboronic acid demonstrates its tanδmax 1.18, Tg = 6.2°C and effective damping temperature range is from −16.4 to 48.5°C. [ABSTRACT FROM AUTHOR]

Purely organic materials exhibiting room temperature phosphorescence (RTP) are promising candidates for oxygen sensors and information encryption owing to their cost‐effective and environmentally friendly nature. Herein, we report a bimolecular RTP system where DTBU acts as the guest and TBBU serves as the host. In contrast to previously reported results, we find that both pure DTBU and TBBU do not exhibit RTP in the solid state even under N2 atmosphere. A DTBU/TBBU system with a low doping ratio (0.1 mol %) exhibits persistent yellowish‐green afterglow with a lifetime of 340 ms and is highly sensitive to oxygen. A DTBU/TBBU system with a higher doping ratio (10 mol %) maintains a phosphorescence lifetime of 179 ms under air. Applications of DTBU/TBBU at varied doping ratios in both oxygen sensing and information encryption are demonstrated. We propose that the T1 state of TBBU acts as an energy transfer intermediate between Tn and T1 of DTBU, ultimately leading to the generation of persistent RTP. Overall, this work demonstrates the critical importance of material purity in the design of RTP systems, and how an understanding of host–guest doping enables their photophysical properties to be precisely tuned. [ABSTRACT FROM AUTHOR]

A series of functional glycopolymer nanoparticles with 1,8‐naphthalimide motif was designed, synthesized and applied for tumor cell imaging. With the pH‐sensitive and aggregation‐induced emission (AIE) effect of the 1,8‐naphthalimide fluorescent probe, the presence of glucose‐based glycopolymers enhanced its water‐solubility and biocompatibility. Owing to the dual tumor‐targeting effects of the dense glucose part and the boronic ester modification, the obtained glycopolymers showed high affinity to tumor cells, with a much faster staining rate than normal cells, indicating a great potential for diagnosis and treatments of cancers. [ABSTRACT FROM AUTHOR]

We report the development of the diastereoselective rhodium(I)‐catalyzed intramolecular conjugate addition (Hayashi‐Miyaura reaction) of robust and easily handled 4‐pinacolboronic ester D‐tryptophan derivatives tethering an activated alkene as the acceptor. This methodology provides, access to the functionalized chiral tricyclic core of the ergoline skeleton diastereoselectivity and allows further modification for the cyclization of the fused fourth ring present in several clavine alkaloids. [ABSTRACT FROM AUTHOR]

An atom transfer radical [3+2] annulation (ATRAn) reaction involving alkenyl boronic esters and homoallylic iodides provides a rapid access to polysubstituted borylated cyclopentanes. A variety of α‐substituted vinylboronic esters are suitable substrates and offer unique opportunities for further modification of the formed 5‐membered ring. For instance, the oxidation of the boronic ester to an alcohol allows the preparation of products that corresponds to an annulation involving the enol form of acetone. Substitution of the iodide by a nucleophile such as lithium methoxide without modifying the boronic ester moiety is also feasible. Finally, by using a (3‐acetoxyprop‐1‐en‐2‐yl)boronic ester, a facile 1,2‐elimination reaction provided a methylenecyclopentane. In this case, the alkenylboronate radical trap acts as an equivalent to allene, a building block so far elusive for preparative radical reactions. [ABSTRACT FROM AUTHOR]

The Suzuki–Miyaura and Buchwald–Hartwig coupling reactions are widely used to form carbon-carbon (C–C) and carbon-nitrogen (C–N) bonds, respectively. We report the incorporation of a formal nitrene insertion process into the Suzuki–Miyaura reaction, altering the products from C–C–linked biaryls to C–N–C–linked diaryl amines and thereby joining the Suzuki–Miyaura and Buchwald–Hartwig coupling pathways to the same starting-material classes. A combination of a bulky ancillary phosphine ligand on palladium and a commercially available amination reagent enables efficient reactivity across aryl halides and pseudohalides, boronic acids and esters, and many functional groups and heterocycles. Mechanistic insights reveal flexibility on the order of bond-forming events, suggesting potential for expansion of the aminative cross-coupling concept to encompass diverse nucleophiles and electrophiles as well as four-component variants. [ABSTRACT FROM AUTHOR]

Donor–π spacer–acceptor (D–π–A) dyes are among the most attractive structures for the design of organic dye-sensitized solar cells (DSSCs). Typically, the key intermediates for these sensitizers are D–π compounds containing an aldehyde group to which an anchor acceptor group is attached via the Knoevenagel reaction. In this communication, 5-(9-(p-tolyl)-2,3,4,4a,9,9a-hexahydro-1H-1,4-methanocarbazol-6-yl)thiophene-2-carbaldehyde was prepared via the Suzuki cross-coupling reaction. The structure of the newly synthesized compound was established by means of high-resolution mass spectrometry, 1H NMR, 13C NMR, IR, and UV–Vis spectroscopy. The title compound would be used in the synthesis of sensitizers for DSSCs. [ABSTRACT FROM AUTHOR]

An outstanding challenge in modern society remains how to make crosslinked polymers (thermosets) more recyclable. A breakthrough solution to this challenge has been the introduction of dynamic covalent bonds in polymer networks, yielding covalent adaptable networks (CANs). Ongoing research is focused on finding new suitable dynamic covalent chemistries and on how to tune the material properties of CANs derived from these new chemistries. Here, we first compare two different dynamic boronic acid based covalent adaptable networks, namely, a conventional boronate‐diol and a novel boronate‐TetraAzaADamantane (TAAD) system. We show that incorporating boronate‐TAAD bonds in networks results in stiffer materials, as seen in a slower relaxation and higher shear and storage moduli. This offers access to more mechanically robust boronate‐based materials, compared to conventional boronate‐based gels. Next, we investigate the effect of molecular tuning via the electron density of meta‐positioned ring substituents on the macroscopic material properties for the boronate‐TAAD network. By comparing relaxation experiments on materials with different substituents, we show that the macroscopic network relaxation can be tuned through the Hammett parameter of the meta‐substituent and the activation energy of the boronate‐TAAD exchange. This enables subtle control over the (dynamic) material properties of these novel, robust boronate‐based networks. [ABSTRACT FROM AUTHOR]

Intracellular protein delivery is critical to the development of protein-based biopharmaceuticals and therapies. However, current delivery vectors often suffer from complicated syntheses, low generality among various proteins, and insufficient serum stability. Herein, we developed an enlightened cytosolic protein delivery strategy by dynamically crosslinking epigallocatechin gallate (EGCG), low-molecular-weight polyethylenimine (PEI 1.8k), and 2-acetylphenylboric acid (2-APBA) on the protein surface, hence forming the EPP-protein nanocapsules (NCs). EGCG enhanced protein encapsulation via hydrogen bonding, and reduced the positive charge density of PEI to endow the NCs with high serum tolerance, thereby enabling effective cellular internalization in serum. The formation of reversible imine and boronate ester among 2-APBA, EGCG, and PEI 1.8k allowed acid-triggered dissociation of EPP-protein NCs in the endolysosomes, which triggered efficient intracellular release of the native proteins. Such strategy therefore showed high efficiency and universality for diversities of proteins with different molecular weights and isoelectric points, including enzyme, toxin, antibody, and CRISPR (clustered regularly interspaced short palindromic repeats)-Cas9 ribonucleoprotein (RNP), outperforming the commercial protein transduction reagent PULSin and RNP transfection reagent lipofectamine CMAX. Moreover, intravenously (i.v.) injected EPP-saporin NCs efficiently delivered saporin into 4T1 tumor cells to provoke robust antitumor effect. This simple, versatile, and robust cytosolic protein delivery system holds translational potentials for the development of protein-based therapeutics. [ABSTRACT FROM AUTHOR]

The conjugated bis-guanidinate (CBG)-supported zinc hydride {LZnH}2; L = {(ArHN)(ArN)–C＝N–C＝(NAr)(NHAr); Ar = 2,6-Et2-C6H3} (I) is utilized as a catalyst for the hydroboration of esters with pinacolborane (HBpin) under mild reaction conditions. Various aryl and alkyl substrates containing electron-donating, withdrawing, and cyclic groups of esters are effectively converted into alkoxy boronate esters as products upon hydroboration. Furthermore, stoichiometric experiments have been performed to understand the plausible reaction mechanism for the hydroboration of esters. Additionally, complex (I) was used for the hydroboration of carbonate, carboxylic acid, and anhydride substrates to showcase the broad substrate scope. [ABSTRACT FROM AUTHOR]

Synthesis of alkyl, aryl, and vinyl boronic esters carrying various chiral and achiral diol‐protecting groups were synthesized starting from the corresponding alkyl, aryl, and vinyl lithium or Grignard reagents. Good to excellent yields were obtained for a large range of substrates. The reaction can be conducted in a gram scale to obtain the product over 80 % yield. This approach provides direct access to neopentyl, pinene, and other boronic esters that are difficult to achieve. Using trimethoxyborane or 2‐isopropoxy pinacolboronic ester. Detailed mechanistic studies have been conducted to understand the mechanism behind the formation of boronic ester starting from organometallic reagents. [ABSTRACT FROM AUTHOR]

The highly stereoselective synthesis of a series of tetrasubstituted mono‐ as well as disilylated vinylboronates is reported by using the boron‐Wittig approach. The condensation between acylsilanes and gem‐diborylalkanes gave the desired tetrasubstituted olefins in good to excellent yield and high stereoselectivity. Also, a series of trisubstituted silylated vinyl MIDA‐boronates was synthesized by using the boron‐Wittig reaction followed by a transesterification reaction. This methodology allows direct incorporation of B(pin) and TMS groups in the anti‐position of the olefin in a highly stereoselective manner. Further, sequential Suzuki coupling reaction with the silylated vinyl boronic esters generated all‐carbon tetrasubstituted alkenes, which have been applied in the total synthesis of the anticancer drug Tamoxifen and aggregation‐induced luminogen agent TPE‐TF17. [ABSTRACT FROM AUTHOR]

Alkenes are an important class of organic molecules found among synthetic intermediates and bioactive compounds. They are commonly synthesized through stoichiometric Wittig‐type olefination of carbonyls and imines, using ylides or their equivalents. Despite the importance of Wittig‐type olefination reactions, their catalytic variants remain underdeveloped. We explored the use of transition metal catalysis to form ylide equivalents from readily available starting materials. Our investigation led to a new copper‐catalyzed olefination of imines with alkenyl boronate esters as coupling partners. We identified a heterobimetallic complex, obtained by hydrocupration of the alkenyl boronate esters, as the key catalytic intermediate that serves as an ylide equivalent. The high E‐selectivity observed in the reaction is due to the stereoselective addition of this intermediate to an imine, followed by stereospecific anti‐elimination. [ABSTRACT FROM AUTHOR]

The direct utilization of simple and abundant feedstocks in carbon‐carbon bond‐forming reactions to embellish sp3‐enriched chemical space is highly desirable. Herein, we report a novel photochemical deoxygenative hydroalkylation of unactivated alkenes with readily available carboxylic acid derivatives. The reaction displays broad functional group tolerance, accommodating carboxylic acid‐, alcohol‐, ester‐, ketone‐, amide‐, silane‐, and boronic ester groups, as well as nitrile‐containing substrates. The reaction is operationally simple, mild, and water‐tolerant, and can be carried out on multigram‐scale, which highlights the utility of the method to prepare value‐added compounds in a practical and scalable manner. The synthetic application of the developed method is further exemplified through the synthesis of suberanilic acid, a precursor of vorinostat, a drug used for the treatment of cutaneous T‐cell lymphoma. A novel mechanistic approach was identified using thiol as a nucleophilic catalyst, which forms a key intermediate for this transformation. Furthermore, electrochemical studies, quantum yield, and mechanistic experiments were conducted to support a proposed catalytic cycle for the transformation. [ABSTRACT FROM AUTHOR]