Asymmetric epoxidation of N-enoylsultams （1, 3-15） incorporating a variety of chiral sultams as the chiral induction elements with UHP/TFAA has been studied. Both diastereomeric isomers of epoxides （2, 16-28） were...Asymmetric epoxidation of N-enoylsultams （1, 3-15） incorporating a variety of chiral sultams as the chiral induction elements with UHP/TFAA has been studied. Both diastereomeric isomers of epoxides （2, 16-28） were obtained in high yield and moderate to high optical purity.展开更多
Several novel chiral thiazoline catalysts containing thiazoline, thiourea and proline were efficiently synthesized from commercially available L-cysteine. These ligands were subsequently applied to the asymmetric Mich...Several novel chiral thiazoline catalysts containing thiazoline, thiourea and proline were efficiently synthesized from commercially available L-cysteine. These ligands were subsequently applied to the asymmetric Michael reaction between cyclohexanone and various β-nitrostyrene. The result shows that the optimal catalyst for this reaction is ligand 18d, the organocatalyst with thiazoline, thiourea and chiral proline motif, which efficiently promotes the enantioselective conjugate addition of cyclohexanone to various nitroalkenes to yield the corresponding addition products in high to excellent yields with enantiomeric excess（e.e.） up to 95% and diastereoselectivity ratio（dr.） up to 99：1.展开更多
Soluble polymeric chiral binaphthol （BINOL） ligands have been synthesized through copolymerization of 3,3′-bis（hydroxymethyl）-2,2′-bis（methoxymethy leneoxy）-1,1′-binaphthyl,1,6-dihydroxyhexane and 1,4-benzene...Soluble polymeric chiral binaphthol （BINOL） ligands have been synthesized through copolymerization of 3,3′-bis（hydroxymethyl）-2,2′-bis（methoxymethy leneoxy）-1,1′-binaphthyl,1,6-dihydroxyhexane and 1,4-benzene dicarbonyl chloride followed by deprotection of methoxymethyleneoxy groups by iPrOH/HCl,and their application in the enantioselective addition of diethylzinc to benzaldehyde was investigated.All soluble polymeric chiral BINOL ligands were characterized by IR、 1H-NMR、GPC and elemental analysis,which clearly demonstrated the formation of polymeric chiral BINOL ligands.These soluble polymeric chiral ligands were found to be effective in the addition of diethylzinc to benzaldehyde either in the presence or in the absence of Ti（Oi Pr）4 with higher catalytic activities and lower enantioselectivities.In the latter case,the dendritic chiral BINOL ligands showed much higher catalytic activity and a little higher enantioselectivity than BINOLs.展开更多
文摘Asymmetric epoxidation of N-enoylsultams （1, 3-15） incorporating a variety of chiral sultams as the chiral induction elements with UHP/TFAA has been studied. Both diastereomeric isomers of epoxides （2, 16-28） were obtained in high yield and moderate to high optical purity.
文摘Several novel chiral thiazoline catalysts containing thiazoline, thiourea and proline were efficiently synthesized from commercially available L-cysteine. These ligands were subsequently applied to the asymmetric Michael reaction between cyclohexanone and various β-nitrostyrene. The result shows that the optimal catalyst for this reaction is ligand 18d, the organocatalyst with thiazoline, thiourea and chiral proline motif, which efficiently promotes the enantioselective conjugate addition of cyclohexanone to various nitroalkenes to yield the corresponding addition products in high to excellent yields with enantiomeric excess（e.e.） up to 95% and diastereoselectivity ratio（dr.） up to 99：1.
文摘Soluble polymeric chiral binaphthol （BINOL） ligands have been synthesized through copolymerization of 3,3′-bis（hydroxymethyl）-2,2′-bis（methoxymethy leneoxy）-1,1′-binaphthyl,1,6-dihydroxyhexane and 1,4-benzene dicarbonyl chloride followed by deprotection of methoxymethyleneoxy groups by iPrOH/HCl,and their application in the enantioselective addition of diethylzinc to benzaldehyde was investigated.All soluble polymeric chiral BINOL ligands were characterized by IR、 1H-NMR、GPC and elemental analysis,which clearly demonstrated the formation of polymeric chiral BINOL ligands.These soluble polymeric chiral ligands were found to be effective in the addition of diethylzinc to benzaldehyde either in the presence or in the absence of Ti（Oi Pr）4 with higher catalytic activities and lower enantioselectivities.In the latter case,the dendritic chiral BINOL ligands showed much higher catalytic activity and a little higher enantioselectivity than BINOLs.
