Short, Enantiospecific Syntheses of Indolizidines 209B and 209D, and Piclavine A from Diethyl-L-Glutamate
作者:Charles W. Jefford、Krzysztof Sienkiewicz、Steven R. Thornton
DOI:10.1002/hlca.19950780610
日期:1995.9.20
8aS)-octahydro-8-hydroxyindolizine-5-carboxylate (22). By functional-group interconversions, 21 was transformed into piclavine A (1) and indolizidine 209D (2). Similarly, (5R,8R,8aS)-octahydro-5-pentylindolizine-8-methanol (37), the final relay for indolizidine 209B (3), was obtained from 22.
从L-谷氨酸二乙酯盐酸盐和四氢-2,5-二甲氧基呋喃中获得的1 H-吡咯衍生物用BBr 3环化为(5 S)-5,6,7,8-四氢-8-氧代吲哚嗪5-羧酸酯(18)。在Pd / C上于AcOH中催化18氢化,得到(5 S,8a R)-八氢吲哚嗪-5-羧酸乙酯(21),而在Rh / Al 2 O 3上于EtOH / AcOH 99:1中进行氢化,主要得到乙基(5 S,8 S,8a S)-八氢-8-羟基吲哚嗪-5-羧酸酯(22)。通过功能组互变,将21转化为吡克拉维甲A(1)和吲哚并立定209D(2)。同样地,从22获得了(5 R,8 R,8a S)-八氢-5-戊基多唑嗪-8-甲醇(37),这是吲哚并立定209B (3)的最终继电器。