A PPh_(3)-catalyzed ring-opening addition reaction of cyclopropenones with alkyl bromides has been successfully established.This reaction offers a concise and practical approach for the assembly ofα,β-disubstituted ...A PPh_(3)-catalyzed ring-opening addition reaction of cyclopropenones with alkyl bromides has been successfully established.This reaction offers a concise and practical approach for the assembly ofα,β-disubstituted acrylates with exclusive E-stereoselectivity at room temperature.Mechanistic investigations indicated that both the hydrogen atom on vinyl group and one oxygen atom on ester group ofα,β-disubstituted acrylates derive from H2O in dimethyl sulfoxide(DMSO).Furthermore,a gram-scale experiment and late-stage modification of the products were accomplished,thereby expanding the application potential of this methodology in organic synthesis.展开更多
α-Chiral amides are common in pharmaceuticals,agrochemicals,natural products,and peptides,prompting the need for new synthetic methods.Here,we introduce a nickel-catalyzed asymmetric reductive amidation method to syn...α-Chiral amides are common in pharmaceuticals,agrochemicals,natural products,and peptides,prompting the need for new synthetic methods.Here,we introduce a nickel-catalyzed asymmetric reductive amidation method to synthesizeα-chiral amides from benzyl ammonium salts and isocyanates.The key to success is using a chiral 2,2-bipyridine ligand(-)-Ph-SBpy,enabling high yield(up to 95%)and enantiomeric ratio(up to 98:2 er)under mild conditions.Addition of phenol prevents isocyanate polymerization by reversibly forming a carbamate intermediate,enhancing selectivity and efficiency.The synthetic utility is showcased through transformations of the enantioenriched amides,and the mechanism and enantioselectivity are supported by experimental and computational studies.展开更多
文摘A PPh_(3)-catalyzed ring-opening addition reaction of cyclopropenones with alkyl bromides has been successfully established.This reaction offers a concise and practical approach for the assembly ofα,β-disubstituted acrylates with exclusive E-stereoselectivity at room temperature.Mechanistic investigations indicated that both the hydrogen atom on vinyl group and one oxygen atom on ester group ofα,β-disubstituted acrylates derive from H2O in dimethyl sulfoxide(DMSO).Furthermore,a gram-scale experiment and late-stage modification of the products were accomplished,thereby expanding the application potential of this methodology in organic synthesis.
基金the National Natural Science Foundation of China(Nos.22150410339,W2432012,22301233 and 22171218)the Ministry of Science and Technology China(No.wgxz2022188)。
文摘α-Chiral amides are common in pharmaceuticals,agrochemicals,natural products,and peptides,prompting the need for new synthetic methods.Here,we introduce a nickel-catalyzed asymmetric reductive amidation method to synthesizeα-chiral amides from benzyl ammonium salts and isocyanates.The key to success is using a chiral 2,2-bipyridine ligand(-)-Ph-SBpy,enabling high yield(up to 95%)and enantiomeric ratio(up to 98:2 er)under mild conditions.Addition of phenol prevents isocyanate polymerization by reversibly forming a carbamate intermediate,enhancing selectivity and efficiency.The synthetic utility is showcased through transformations of the enantioenriched amides,and the mechanism and enantioselectivity are supported by experimental and computational studies.
