A visible light-mediated ring expansion reaction of cyclic N-sulfenyl sulfoximines with aryl diazoacetates is presented.The protocol results in the formation of six-membered heterocycles through the formation of sulfu...A visible light-mediated ring expansion reaction of cyclic N-sulfenyl sulfoximines with aryl diazoacetates is presented.The protocol results in the formation of six-membered heterocycles through the formation of sulfur ylide intermediates and a subsequent[1,2]-sigmatropic rearrangement.The reaction proceeds well under ambient conditions and gives the desired heterocycles in moderate to good yields with a good functional group tolerance.Subsequent oxidation of the products with m-CPBA results in significant diastereomeric enrichment of the products.Density functional theory studies indicate that the diastereoconvergent oxidation is enabled by a ring opening and recyclization,which allow the diastereomeric ratio to adjust to a value governed by the differing thermodynamic stabilities of the diastereomers.展开更多
Difluoromethyl ethers are formed through mechanochemical reactions of alcohols with difluorocarbene in a mixer mill.The protocol could be applied to primary,secondary,and tertiary alcohols,yielding the corresponding p...Difluoromethyl ethers are formed through mechanochemical reactions of alcohols with difluorocarbene in a mixer mill.The protocol could be applied to primary,secondary,and tertiary alcohols,yielding the corresponding products in excellent yields(up to 99%)after 1 h reaction time at room temperature.The transformations proceeded under solvent-free reaction conditions,followed by product purification by filtration,which drastically reduced the amount of waste generated during the process.展开更多
基金P.Wu,Y.Tu,and Y.Hu are grateful to the China Scholarship Council for predoctoral stipends,and we acknowledge the Alexander von Humboldt Foundation for support of K.Rissanen(AvH research award).Simulations were performed with computing resources granted by RWTH Aachen University under project rwth 1465.
文摘A visible light-mediated ring expansion reaction of cyclic N-sulfenyl sulfoximines with aryl diazoacetates is presented.The protocol results in the formation of six-membered heterocycles through the formation of sulfur ylide intermediates and a subsequent[1,2]-sigmatropic rearrangement.The reaction proceeds well under ambient conditions and gives the desired heterocycles in moderate to good yields with a good functional group tolerance.Subsequent oxidation of the products with m-CPBA results in significant diastereomeric enrichment of the products.Density functional theory studies indicate that the diastereoconvergent oxidation is enabled by a ring opening and recyclization,which allow the diastereomeric ratio to adjust to a value governed by the differing thermodynamic stabilities of the diastereomers.
基金research was made possible by the generous support of the Rhine-Westphalia Technical University of Aachen(RWTH Aachen University)We also acknowledge the Alexander von Humboldt Foundation for support of K.R.(AvH research award).
文摘Difluoromethyl ethers are formed through mechanochemical reactions of alcohols with difluorocarbene in a mixer mill.The protocol could be applied to primary,secondary,and tertiary alcohols,yielding the corresponding products in excellent yields(up to 99%)after 1 h reaction time at room temperature.The transformations proceeded under solvent-free reaction conditions,followed by product purification by filtration,which drastically reduced the amount of waste generated during the process.
