Methyl 3α-1,2,3,4,6,7,12,12bβ-cotahydroindolo[2,3-a]quinolizine-1α-carboxylate (6), a key intermediate for the synthesis of tacamine-type indole alkaloids, was prepared in six simple steps from methyl 5-(1′-hydroxyethyl)nicotinate (7). The last step was the catalytic hydrogenation of the two ethylidene isomers 14 and 15, both of which gave the target ester stereoselectively.
3α-1,2,3,4,6,7,12,12bβ-cotahydroindolo[2,3- a ] quinolizine -1α-
羧酸盐(6)是合成他卡明型
吲哚生物碱的关键中间体。由五个简单的步骤由5-(1'-羟乙基)
烟酸甲酯(7)制备。最后一步是两个亚乙基异构体14和15的催化加氢,这两个异构体均立体选择性地提供了目标酯。