Synthesis of 1,12b-didehydrolycoran (α-anhydrodihydrocaranine) and 12bα-lycoran (γ-lycoran)via photocyclisation of an enamide-ketone
作者:Hideo Iida、Sakae Aoyagi、Chihiro Kibayashi
DOI:10.1039/p19750002502
日期:——
A novel stereoselective synthesis of lycorine-type alkaloids from a key intermediate obtained by photocyclisation of an enamido-ketone is described. Birch reduction of 6-methoxyindoline, prepared by a benzyne reaction of 3-chloro-4-methoxyphenethylamine, gave 3,3a,4,5-tetrahydro-6-methoxy-2H-indole (18) which reacted with benzoyl and 3,4-methylenedioxybenzoyl chloride to form the corresponding N-acylindol-6-one
描述了一种新的立体选择性合成的lycorine型生物碱从关键中间体通过烯胺酮的光环化获得。通过3-氯-4-甲氧基苯乙胺的苯炔反应制备的6-甲氧基二氢吲哚桦木还原,得到3,3a,4,5-四氢-6-甲氧基-2 H-吲哚(18),其与苯甲酰基和3, 4-亚甲基二氧基苯甲酰氯形成相应的N -acylindol-6-one衍生物(20)和(21)。两种烯胺酮的照射分别产生吡咯并[3,2,1- de ]菲啶衍生物(22)和(23)。在用氢化锂铝处理后,将后者(23)立体选择性地转化为(±)-1,12b-二氢二氢呋喃(3),然后将其氢化为(±)-12bα-二氢呋喃(5)。