Synthetic Efforts and Ultimate Limitation to an Asymmetric Achmatowicz Approach Toward EBC-23
作者:Yanping Wang、George A. O’Doherty
DOI:10.1021/acs.joc.2c00262
日期:2022.5.6
The asymmetric approach is convergent and uses a late-stage Claisen-like enolate/acid chloride coupling to establish a key 1,3-diketone intermediate. The 1,3-diketone target is an oxidized form of the hydrated natural product, which fails to spiroketalize. The convergent asymmetric synthesis uses an asymmetric Noyori transfer hydrogenation of a β-furyl ketoester to enantioselectively form a chiral furyl
An efficient asymmetric synthesis of (+)-tetrahydropseudodistomin is described. The important synthetic features include a Maruoka asymmetric allylation and a Sharpless asymmetric dihydroxylation as key steps for the generation of chirality at C-2, -4, and -5 of the trisubstituted piperidine ring. (c) 2007 Elsevier Ltd. All rights reserved.
An Improved Asymmetric Synthesis of Malyngamide U and Its 2′-Epimer
作者:Jian-Peng Feng、Zi-Fa Shi、Yang Li、Jun-Tao Zhang、Xian-Liang Qi、Jie Chen、Xiao-Ping Cao
DOI:10.1021/jo800876u
日期:2008.9.1
An accelerated and improved asymmetric synthesis of malyngamide U (1) and its 2'-epimer (2'-epi-1) was accomplished from readily available n-hexanal, ethanolamine and (R)-(-)-carvone. The key steps involved a Johnson-Claisen rearrangement in the synthesis of an unsaturated carboxylic acid 4 and an aldol reaction in the construction of the skeleton of I and 2'-epi-1. There are 13 steps in the synthesis, with a 2.7% overall yield for 1 and a 0.4% yield for 2'-epi-1.
First stereoselective synthesis of serinol-derived malyngamides and their 1′-epi-isomers
作者:Jie Chen、Yang Li、Xiao-Ping Cao
DOI:10.1016/j.tetasy.2006.02.027
日期:2006.3
A stereoselective synthesis of 1a N-[(1R)-2-hydroxy-1-methoxy-methyl ethyl]-(4E,7S)-7-methoxy-4-eicosenamide} has been accomplished in 10 steps from 1-tetradecanol for the first time in 28% overall yield. The key steps involved the coupling reaction of a chiral alkyne with a protected bromide in the presence of t-BuLi, as well as the amidation reaction of (4E,7S)-7-methoxyeicos-4-enoic acid with (R)-methoxyamino
从1开始的10个步骤完成了1a N -[(1 R)-2-羟基-1-甲氧基-甲基乙基]-(4 E,7 S)-7-甲氧基-4-二十碳酰胺}的立体选择性合成十四烷醇的总收率首次达到28%。关键步骤涉及在t- BuLi存在下手性炔烃与受保护的溴化物的偶合反应,以及(4 E,7 S)-7-甲氧基表面四烯酸与(R)的酰胺化反应。-甲氧基氨基醇。乙酰化1a完成1b N -[(1 S)-2-乙酰氧基-1-甲氧基-甲基乙基]-(4 E,7 S)-7-甲氧基-4-二十碳酰胺}。它们的1'-表位异构体也已经以相似的策略合成。