Asymmetric azo-ene reactions using the chiral azo-enophile di-(−)-(1R,2S)-2-phenyl-1-cyclohexyl diazenedicarboxylate
作者:Margaret A Brimble、Connie K.Y Lee
DOI:10.1016/s0957-4166(98)00034-2
日期:1998.3
The preparation of di-(−)-(1R,2S)-2-phenyl-1-cyclohexyl diazenedicarboxylate 4 is described. Reaction of (1R,2S)-2-phenyl-1-cyclohexanol 1 with excess phosgene in the presence of quinoline afforded chloroformate 2 which was treated directly with hydrazine monohydrate (0.5 equiv.) to afford di-(−)-(1R,2S)-2-phenyl-1-cyclohexyl diazanedicarboxylate 3. Oxidization of 3 to the azo-enophile 4 was then readily