Two dienes comprising the complete heavy-atom framework of the macrocyclic core of the marine macrolide leiodolide A were prepared by esterification of an appropriate carboxylic acid and two alcohol building blocks. The latter were obtained in a stereoselective fashion from ( R )-citronellal via a Crimmins-type aldol reaction, oxidative double bond cleavage, and efficient oxazole formation as the key
包含海洋大环内酯类碘内酯 A 的大环核心的完整重原子骨架的两种二烯是通过适当的羧酸和两种醇结构单元的酯化反应制备的。后者是通过 Crimmins 型羟醛反应、氧化双键断裂和有效恶唑形成作为关键转化从 ( R )-香茅醛以立体选择性方式获得的。在不同条件下研究了可能的基于闭环复分解 (RCM) 的二烯大环化。在任何这些实验中都没有获得环化产物,因此表明 C6 和 C7 之间的 RCM 可能不是 leiodolide A 全合成的可行策略。
Synthesis of C1–C20 and C21–C40 fragments of tetrafibricin
作者:Venugopal Gudipati、Dennis P. Curran
DOI:10.1016/j.tetlet.2011.01.086
日期:2011.4
Efficient syntheses of suitably functionalized top and bottom fragments of tetrafibricin are described. The bottom fragment is prepared by two consecutive Kocienski-Julia couplings, while the top fragment synthesis features a dithiane alkylation and a Horner-Wadsworth-Emmons reaction. (C) 2011 Elsevier Ltd. All rights reserved.
Spirodiepoxide Strategy to the C Ring of Pectenotoxin 4: Synthesis of the C1−C19 Sector
作者:Sipak Joyasawal、Stephen D. Lotesta、N. G. Akhmedov、Lawrence J. Williams
DOI:10.1021/ol902984e
日期:2010.3.5
The synthesis of a C1-C19 precursor to pectenotoxin 4 is presented, The strategy employed the functionalized allene shown. Key features include: olefin metathesis of two simple fragments to prepare the left portion of the allene-precursor, diastereoselective propargylation of an epoxy aldehyde to form the right portion, use of the DMDO-stable m-fluorobenzyl ether, and an allene spirodiepoxidation/C-ring formation cascade.