Kingsbury Jason S, Corey E J
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
J Am Chem Soc. 2005 Oct 12;127(40):13813-5. doi: 10.1021/ja055137+.
A new synthetic strategy for the enantioselective synthesis of members of the dolabellane family of marine natural products has been demonstrated for the specific examples beta-araneosene and isoedunol (1 and 2, respectively) by the pathway outlined in Scheme 1. Key steps include (1) diastereoselective alkylation of Seebach's chiral lactate acetal (6) by the iodide derived from 5; (2) Kulinkovich ethylenation of ester 9 to form the cyclopropanol 10; (3) ring expansion of 10 to form 11; (4) pinacol cyclization of keto aldehyde 12 to form 13a; (5) rearrangement of 13b to 14; (6) propenylation of 14 to 2; and (7) reductive pi-transposition to form 1.
通过方案1中概述的途径，已针对特定实例β-蜘蛛烯和异埃杜醇（分别为1和2）展示了一种对海洋天然产物多拉贝拉烷家族成员进行对映选择性合成的新合成策略。关键步骤包括：（1）由5衍生的碘化物对西巴赫手性乳酸缩醛（6）进行非对映选择性烷基化；（2）酯9的库林科维奇乙烯化反应以形成环丙醇10；（3）10的扩环反应以形成11；（4）酮醛12的频哪醇环化反应以形成13a；（5）13b重排为14；（6）14烯丙基化为2；以及（7）还原π-迁移以形成1。
