Facile access to optically active ring C aromatic diterpene derivatives from manool. Highly efficient syntheses of (+)-12-methyl-7-oxo-podocarpa-8,11,13-triene-13-carboxylic acid, (+)-13-methyl-7-oxopodocarpa-8,11,13-triene-12-carboxylic acid and (+)-nimbiol
作者:Tatsuhiko Nakano、Randolph Alonso、María Aracelis Maillo、Alfonso Martín、Ramona Avila Núñez
DOI:10.1039/a708795k
日期:——
The extension of our recently developed strategy using the key intermediate 2, obtainable in two steps (52% overall yield) from manool 1, to the synthesis of naturally occurring ring C aromatic diterpene derivatives provides in three steps (+)-12-methyl-7-oxopodocarpa-8,11,13-triene-13-carboxylic acid 4b and its isomer 6b, and in seven steps (+)-nimbiol 11b, in good overall yields. This synthesis discloses that the structure 4b assigned to margolone isolated from Azadirachta indica A. Juss is incorrect and needs to be reinvestigated.
我们最近开发的策略的扩展,利用关键中间体2,该中间体可通过两步反应(总体收率52%)从马诺醇1获得,对天然存在的C环芳香二萜衍生物的合成提供了在三步内合成(+)-12-甲基-7-氧基波多卡尔帕-8,11,13-三烯-13-羧酸4b及其异构体6b,并且在七步内合成(+)-宁比醇11b,均获得了良好的总体收率。这一合成揭示了分配给从印度苦楝(Azadirachta indica A. Juss)中分离的马戈隆4b的结构是错误的,需要重新调查。