An efficient synthesis of (±)-crinane using an intramolecular azide-olefin cycloaddition
作者:Jeffrey M Schkeryantz、William H Pearson
DOI:10.1016/0040-4020(95)01098-x
日期:1996.2
proceeds by intramolecular 1,3-dipolar cycloaddition of the azide onto the alkene followed by loss of nitrogen from the triazoline intermediate to give an imine. Reduction of the imine 12 with sodium cyanoborohydride in acetic acid/THF gave (3aR∗, 7aR∗)-3a-[3,4-methylenedioxy)phenyl]-2,3,3a,4,5,6,7,7a-octahydroindole (13). Warming 13 with Eschenmoser's salt provided (±)-crinane (1). The synthesis of (±)-crinane
将3-(2-叠氮基乙基)-3- [3,4-(亚甲基二氧基)苯基]环己-1-烯(2)在甲苯中回流24小时,得到3a- [3,4-亚甲基二氧基)苯基] -3,3a ,4,5,6,7-六氢-2 H-吲哚(12)的定量收率。该反应通过将叠氮化物的分子内1,3-偶极环加成到烯烃上,然后从三唑啉中间体中损失氮而得到亚胺来进行。用氰基硼氢化钠在乙酸/ THF中还原亚胺12,得到(3aR ∗,7aR ∗)-3a- [3,4-亚甲二氧基)苯基] -2,3,3a,4,5,6,7,7a-八氢吲哚(13)。升温13与Eschenmoser的盐的形式提供(±)-crinane(1)。由环己烯酮合成(±)-氢化正庚烷(1)分8步完成,总产率为23%。