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Abstract A practical method is introduced for the catalytic conversion of terminal alkynes into α-substituted vinyl boronic esters. The process employs catalytic amounts of nanoparticle-supported gold catalysts and catalytic amounts of copper to effect the overall transformation. 

Abstract Since Friedrich Wöhler's groundbreaking synthesis of urea in 1828, organic synthesis over the past two centuries has predominantly relied on the exploration and utilization of chemical reactions rooted in two‐electron heterolytic ionic chemistry. While one‐electron homolytic radical chemistry is both rich in fundamental reactivities and attractive with practical advantages, the synthetic application of radical reactions has been long hampered by the formidable challenges associated with the control over reactivity and selectivity of high‐energy radical intermediates. To fully harness the untapped potential of radical chemistry for organic synthesis, there is a pressing need to formulate radically different concepts and broadly applicable strategies to address these outstanding issues. In pursuit of this objective, researchers have been actively developing metalloradical catalysis (MRC) as a comprehensive framework to guide the design of general approaches for controlling over reactivity and stereoselectivity of homolytic radical reactions. Essentially, MRC exploits the metal‐centered radicals present in open‐shell metal complexes as one‐electron catalysts for homolytic activation of substrates to generate metal‐entangled organic radicals as the key intermediates to govern the reaction pathway and stereochemical course of subsequent catalytic radical processes. Different from the conventional two‐electron catalysis by transition metal complexes, MRC operates through one‐electron chemistry utilizing stepwise radical mechanisms. 

Abstract The ability to efficiently and selectively process mixed polymer waste is important to address the growing plastic waste problem. Herein, we report that the combination of ZnCl₂and an additive amount of poly(ethylene glycol) under vacuum can readily and selectively depolymerize polyesters and polycarbonates with high ceiling temperatures (T_c>200 °C) back to their constitute monomers. Mechanistic experiments implicate a random chain scission mechanism and a catalyst structure containing one equivalent of ZnCl₂per ethylene glycol repeat unit in the poly(ethylene glycol). In addition to being general for a wide variety of polyesters and polycarbonates, the catalyst system could selectively depolymerize a polyester in the presence of other commodity plastics, demonstrating how reactive distillation using the ZnCl₂/PEG600 catalyst system can be used to separate mixed plastic waste. 

Abstract Cysteine bioconjugation serves as a powerful tool in biological research and has been widely used for chemical modification of proteins, constructing antibody‐drug conjugates, and enabling cell imaging studies. Cysteine conjugation reactions with fast kinetics and exquisite selectivity have been under heavy pursuit as they would allow clean protein modification with just stoichiometric amounts of reagents, which minimizes side reactions, simplifies purification and broadens functional group tolerance. In this concept, we summarize the recent advances in fast cysteine bioconjugation, and discuss the mechanism and chemical principles that underlie the high efficiencies of the newly developed cysteine reactive reagents. 

Abstract Direct synthesis of CH₃COOH from CH₄and CO₂is an appealing approach for the utilization of two potent greenhouse gases that are notoriously difficult to activate. In thisCommunication, we report an integrated route to enable this reaction. Recognizing the thermodynamic stability of CO₂, our strategy sought to first activate CO₂to produce CO (through electrochemical CO₂reduction) and O₂(through water oxidation), followed by oxidative CH₄carbonylation catalyzed by Rh single atom catalysts supported on zeolite. The net result was CH₄carboxylation with 100 % atom economy. CH₃COOH was obtained at a high selectivity (>80 %) and good yield (ca. 3.2 mmol g⁻¹_catin 3 h). Isotope labelling experiments confirmed that CH₃COOH is produced through the coupling of CH₄and CO₂. This work represents the first successful integration of CO/O₂production with oxidative carbonylation reaction. The result is expected to inspire more carboxylation reactions utilizing preactivated CO₂that take advantage of both products from the reduction and oxidation processes, thus achieving high atom efficiency in the synthesis.