Divergent Approach to Gabosines and Anhydrogabosines: Enantioselective Syntheses of (+)-Epiepoformin, (+)-EpoKformin, (+)-Gabosine A, and Gabosines B and F
作者:Gladis Toribio、Georgina Marjanet、Ramon Alibés、Pedro de March、Josep Font、Pau Bayón、Marta Figueredo
DOI:10.1002/ejoc.201001527
日期:2011.3
A divergentapproach to polyoxygenated methylcyclohexanes has been applied to synthesize several gabosines and anhydrogabosines. The starting hydroxycyclohexenone, which is readily available in any antipodal form, provides access to both enantiomers of the target compounds. The syntheses of anhydrogabosines involve three main transformations: α-methylation, epoxidation, and sulfur removal, whereas
一种不同的聚氧化甲基环己烷方法已被应用于合成几种 gabosines 和 anhydrogabosines。起始羟基环己烯酮很容易以任何对映体形式获得,提供了获得目标化合物的两种对映异构体的途径。anhydrogabosines 的合成涉及三个主要转化:α-甲基化、环氧化和脱硫,而 gabosines 的合成需要额外的环氧化物水解步骤。该策略已应用于合成 (+)-epiepoformin、(+)-epoformin、(+)-gabosine A 以及 gabosines B 和 F,通过简单的序列以良好的总产率合成。
Stereoselective Synthesis and Relative Configuration Assignment of Gabosine J
its enantiomer have been accomplished through an enantioselective approach from a common intermediate 1. These syntheses have allowed us to establish the correct relative configuration of the natural metabolite, which was originally misassigned. This work, together with our former syntheses of other gabosines and related compounds, validates enone 1 as a general synthetic precursor for this kind of
new synthesis of (+)-gabosine C has been accomplished as part of a general diversity-oriented approach that also delivered the previously unknown (−)-4-epi-gabosine C. The identification of the unexpected intermediate (+)-8, together with the isolation of ketones 9 and 10 in previous investigations, prompted us to formulate a new hypothesis for the biosynthesis of gabosines, based on a keto–enol equilibrium