Potential intermediate, (±)-di-o-acetyl-3α-phenylselanyl-3,3a-dihydro-<scp>B</scp>-nor-6,7a-secolycorin-5-one for synthesis of the Amaryllidaceae alkaloid lycorine: formal and total syntheses of (±)-lycorine
作者:Osamu Hoshino、Miyuki Ishizaki、Keisuke Kamei、Minoru Taguchi、Takashi Nagao、Kiyoshi Iwaoka、Shohei Sawaki、Bunsuke Umezawa、Yoichi Iitaka
DOI:10.1039/p19960000571
日期:——
Formal and total syntheses of the Amaryllidaceae alkaloid, (±)-lycorine 1, were achieved by new synthetic routes via(±)-di-o-acetyl-3α-phenylselanyl-3,3a-dihydro-B-nor-6,7a-secolycorin-5-one 32. Namely, stereoselective intramolecular Diels–Alder reaction of triene ester 5 afforded, in good yield, the cis-lactone 6, which was converted into β(stereochemical)-hydroxy-γ-lactam 23. Oxidation of silyl ether
的正式和全合成石蒜科生物碱,(±)-lycorine 1中,通过新的合成途径来实现经由(±) -二- ø -乙酰基3α-phenylselanyl基-3,3a二氢乙-nor-6,7A -secolycorin-5-one 32.即,三烯酸酯5的立体选择性分子内Diels-Alder反应提供了高收率的顺式-内酯6,该顺式-内酯6转化为β(立体化学)-羟基-γ-内酰胺23。甲硅烷基用醚24米氯过苯甲酸,得到仅β-(叔-丁基二甲基甲硅烷氧基)-α-环氧化物25,其立体结构由其X射线晶体学分析确定。化合物25的Payne重排和连续的乙酰化提供了α(立体化学)-乙酰氧基-β(立体化学)-环氧γ-内酰胺29,通过B环的构建将其转化为(±)-lycorine 1。还描述了(±)-lycorine 1的正式全合成。