Department of Chemistry, Faculty of Science, Hokkaido University , Sapporo 060-0810, Japan.
Faculty of Pharmaceutical Sciences, Tokyo University of Science , Noda-shi, Chiba 278-8525, Japan.
Org Lett. 2017 Feb 17;19(4):922-925. doi: 10.1021/acs.orglett.7b00085. Epub 2017 Jan 27.
(+)-Iso-A82775C is a proposed biosynthetic precursor of the chloropupukeananin family and an important intermediate for related natural products. The first enantioselective total synthesis of (+)-iso-A82775C (18 steps, 2.2% overall yield) toward the eventual biomimetic total synthesis of chloropupukeananin is described. The key steps are (1) the enantioselective Diels-Alder reaction of 4-bromo-3-hydroxy-2-pyrone with methyl 2-chloroacrylate using cinchonine as an organocatalyst and (2) the anti-selective Cu-mediated S2' reaction to afford the axially chiral vinylallene moiety.
（+）-Iso-A82775C 是一种拟生源的氯棕酮烷类化合物，也是相关天然产物的重要中间体。本文描述了（+）-Iso-A82775C（18 步，总产率 2.2%）的第一个对映选择性全合成，这是最终进行生物模拟全合成氯棕酮烷的重要中间体。关键步骤是：（1）使用金鸡纳碱作为有机催化剂，对 4-溴-3-羟基-2-吡喃酮和甲基 2-氯丙烯酸酯进行对映选择性 Diels-Alder 反应；（2）反选择性的 Cu 介导 S2'反应，得到轴向手性乙烯基烯丙基部分。
