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
描述了二-(-)-(1 R,2 S)-2-苯基-1-环己基二氮杂二羧酸4的制备。(1 R,2 S)-2-苯基-1-环己醇1与过量的光气在喹啉存在下反应,得到氯甲酸酯2,将其直接用一水合肼(0.5当量)处理,得到二-(-)-( 1 R,2 S)-2-苯基-1-环己基二氮杂二羧酸酯3。然后使用N-溴代琥珀酰亚胺和吡啶容易地以高收率将3氧化成偶氮亲电子体4。的偶氮-烯反应4使用路易斯酸氯化锡(IV)与烯烃的环己烯5,环戊烯6,反式-3-己烯7和反式-4-辛烯8与烯烃进行反应。使用环己烯5可获得80%收率的烯加合物9,非对映体过量> 97:3,而使用环戊烯6,反-3-己烯7和反-4-辛烯8可获得烯加合物10(77% ),11(71%)和12(92%),在每种情况下,非对映异构体过量为86:14。使用共轭芳族无环烯烃13得到离子加成产物,即氯化物14,收率为57%。使用液态氨中的锂进行烯键加合物9的