Transition-metal catalyzed cross-couplings of aryl halides(ArI,ArBr and ArCl)with a broad range of nucleophiles have been developed as powerful methods for carbon-carbon and carbon-heteroatom bonds formation.However,d...Transition-metal catalyzed cross-couplings of aryl halides(ArI,ArBr and ArCl)with a broad range of nucleophiles have been developed as powerful methods for carbon-carbon and carbon-heteroatom bonds formation.However,due to the high bond dissociation energy of unactivated C(sp^(2))-F,cross-couplings of mono-fluoroarenes are the most challenging,especially without using transition-metal catalysts.Herein,a photo-induced transition-metal and external photosensitizer free defluorophosphonation of monofluoroarenes via unactivated C(sp^(2))-F bond cleavage is reported.Different mono-fluoroarenes have been successfully cross-coupled with dialkyl phosphites in moderate to excellent yields under mild conditions.Mechanistic studies have revealed the possible involvement of a photo-induced SET process and aryl free radical intermediates.展开更多
Wereport a base-promoted catalyst-free protocol for the highly regioselective hydroacylation of styrenes with hydrazones derived from naturally abundant aldehydes.This protocolgeneratedlinearketoneswith goodfunctional...Wereport a base-promoted catalyst-free protocol for the highly regioselective hydroacylation of styrenes with hydrazones derived from naturally abundant aldehydes.This protocolgeneratedlinearketoneswith goodfunctional grouptolerance anda broadsubstrate scope under mild conditions.Mechanistic studies showed that the addition of hydrazone anion to a styrene double bond was the key step,different from previoushydroacylationpathways(viaorganometallic complexes or radical intermediates).展开更多
Acyl fluorides are powerful synthons for acylation with wide application in the synthesis of valued compounds,especially peptides.Herein,a practical and catalyst-free method for the synthesis of acyl fluorides from al...Acyl fluorides are powerful synthons for acylation with wide application in the synthesis of valued compounds,especially peptides.Herein,a practical and catalyst-free method for the synthesis of acyl fluorides from aldehydes via C(sp^(2))-H fluorination is reported.This method enables the conversion of both aliphatic and aromatic aldehydes into acyl fluorides in good to excellent yields by visible-light under mild conditions in the absence of transition-metal and external photosensitizer.A variety of functional groups were well tolerated for this transformation.This green method provides a practical pathway to synthesize acyl fluorides under mild conditions.展开更多
基金support from the NSFC(Grant No.21971093)the International Joint Research Centre for Green Catal-ysis and Synthesis(Grants No.2016B01017 and 18JR4RA003)。
文摘Transition-metal catalyzed cross-couplings of aryl halides(ArI,ArBr and ArCl)with a broad range of nucleophiles have been developed as powerful methods for carbon-carbon and carbon-heteroatom bonds formation.However,due to the high bond dissociation energy of unactivated C(sp^(2))-F,cross-couplings of mono-fluoroarenes are the most challenging,especially without using transition-metal catalysts.Herein,a photo-induced transition-metal and external photosensitizer free defluorophosphonation of monofluoroarenes via unactivated C(sp^(2))-F bond cleavage is reported.Different mono-fluoroarenes have been successfully cross-coupled with dialkyl phosphites in moderate to excellent yields under mild conditions.Mechanistic studies have revealed the possible involvement of a photo-induced SET process and aryl free radical intermediates.
基金from the National Natural Science Foundation of China(grant no.21971093)the International Joint Research Centre for Green Catalysis and Synthesis(grant no.2016B01017),and the 111 project.
文摘Wereport a base-promoted catalyst-free protocol for the highly regioselective hydroacylation of styrenes with hydrazones derived from naturally abundant aldehydes.This protocolgeneratedlinearketoneswith goodfunctional grouptolerance anda broadsubstrate scope under mild conditions.Mechanistic studies showed that the addition of hydrazone anion to a styrene double bond was the key step,different from previoushydroacylationpathways(viaorganometallic complexes or radical intermediates).
基金We thank the NSFC(No.21971093)the International Joint Research Centre for Green Catalysis and Synthesis(No.2016B01017)the 111 projects for support of our research.We also thank the Canada Research Chair(Tier I)foundation,the E.B.Eddy Endowment Fund,the Canada Foundation for Innovation,and the Natural Sciences and Engineering Research Council of Canada to Chao-Jun Li.
文摘Acyl fluorides are powerful synthons for acylation with wide application in the synthesis of valued compounds,especially peptides.Herein,a practical and catalyst-free method for the synthesis of acyl fluorides from aldehydes via C(sp^(2))-H fluorination is reported.This method enables the conversion of both aliphatic and aromatic aldehydes into acyl fluorides in good to excellent yields by visible-light under mild conditions in the absence of transition-metal and external photosensitizer.A variety of functional groups were well tolerated for this transformation.This green method provides a practical pathway to synthesize acyl fluorides under mild conditions.
