ABSTRACT Diastereoselective firsttotalsynthesis of parvistone C 1 and C8-epimer 1a are described. The key features of our synthesis include Sharpless asymmetric dihydroxylation, stereoselective aryl Grignard reactions, Still–Gennari olefination, and intramolecular cyclization. GRAPHICAL ABSTRACT
摘要描述了非对映选择性第一次全合成 parvistone C 1 和 C8-差向异构体 1a。我们合成的主要特征包括 Sharpless 不对称二羟基化、立体选择性芳基格氏反应、Still-Gennari 烯化和分子内环化。图形概要
Stereoselective preparation of trisubstituted (Z)-alkenes; synthesis of the C17–C27 fragment of (−)-laulimalide
A Ni-catalyzed cross-coupling reaction of (Z)-5-(tert-butyldiphenylsilyl)oxy-3-bromo-1-trimethylsilyl-3-penten-1-yne (1) with alkyl Grignard reagent gives (Z)-3-alkyl-5-(tert-butyldiphenylsilyl)oxy-1-trimethylsilyl-3-penten-1-ynes (2) stereospecifically in good yields. The (Z)-enyne 2a is transformed in four steps to (Z)-3-methyl-5-silyloxy-3-pentenaI (3), which is coupled with ketophosphonate 4 to give enone 13. The eta-hydroxyallyl methanesulfonate derived from 13 is cyclized to 3,6-dihydro[2H]pyran by an intramolecular SN2' reaction stereoselectively, furnishing a C17-C27 carbon unit of (-)-laulimalide. (C) 2005 Elsevier Ltd. All rights reserved.
Enantioselective Total Synthesis of (+)-EBC-23, a Potent Anticancer Agent from the Australian Rainforest
作者:Arun K. Ghosh、Che-Sheng Hsu
DOI:10.1021/acs.joc.1c00172
日期:2021.5.7
here an enantioselective synthesis of (+)-EBC-23, a potent anticancer agent from the Australian rainforest. Our convergent synthesis features a [3+2] dipolar cycloaddition of an olefin-bearing 1,3-syn diol unit and an oxime segment containing 1,2-syn diol functionality as the key step. The segments were synthesized in a highly enantioselective manner using Noyori asymmetric hydrogenation of a β-keto