Stereoselective Synthesis of Highly Substituted .gamma.-Lactones and Butenolides by Intramolecular Michael Addition of Enantiomerically Enriched .gamma.-[(Phenylthio)acyl]oxy .alpha.,.beta.-Unsaturated Esters
摘要:
The synthesis of polysubstituted gamma-lactones by the base-induced cyclization of enantiomerically enriched gamma-((phenylthio)acyl)oxy alpha,beta-unsaturated esters obtained from 2,3-epoxy alcohols is described. The procedure is highly stereoselective and compatible with a wide range of functionalities (ester, tetrahydropyranyl ether, silyl ether, etc.). Varying degrees of substitution, including quaternary centers, in the final gamma-lactone were synthesized with excellent stereoselectivity. Useful functional interconversions were successfully demonstrated, in particular those resulting in butenolides. By the use of AM1 it was concluded that the intramolecular Michael reaction can be described as a kinetically controlled reaction in which the relative stability of the transition states for all possible final configurations led to geometries in agreement with the experimental results.
peptidic fragment and a new asymmetricmethodology of epoxidation for the preparation of the lipidic chain. The linkage between both fragments was successfully achieved in solid phase to complete the syntheses via a macrolactonization reaction executed prior to the cleavage of the acyclic precursors from the solid support. These syntheses provide access to the rapid generation of a library of analogues
报道了天然脂环二肽类抗生素球霉素和SF-1902 A 5的合成,利用固相技术构建了肽片段,并采用了一种新的不对称环氧化方法来制备脂质链。两个片段之间的键合在固相中成功完成,通过在从固体载体上裂解无环前体之前进行的大环内酯化反应完成了合成。这些合成物通过修饰氨基酸残基和脂质链提供了快速生成类似物文库的途径,从而基于对酶信号肽酶II的抑制,促进了具有有趣作用机制的新抗生素的鉴定。
Stereoselective Synthesis of Highly Substituted .gamma.-Lactones and Butenolides by Intramolecular Michael Addition of Enantiomerically Enriched .gamma.-[(Phenylthio)acyl]oxy .alpha.,.beta.-Unsaturated Esters
作者:Carmen M. Rodriguez、Tomas Martin、Miguel A. Ramirez、Victor S. Martin
DOI:10.1021/jo00095a022
日期:1994.8
The synthesis of polysubstituted gamma-lactones by the base-induced cyclization of enantiomerically enriched gamma-((phenylthio)acyl)oxy alpha,beta-unsaturated esters obtained from 2,3-epoxy alcohols is described. The procedure is highly stereoselective and compatible with a wide range of functionalities (ester, tetrahydropyranyl ether, silyl ether, etc.). Varying degrees of substitution, including quaternary centers, in the final gamma-lactone were synthesized with excellent stereoselectivity. Useful functional interconversions were successfully demonstrated, in particular those resulting in butenolides. By the use of AM1 it was concluded that the intramolecular Michael reaction can be described as a kinetically controlled reaction in which the relative stability of the transition states for all possible final configurations led to geometries in agreement with the experimental results.
A synthesis of allylic alcohols from β-γ-epoxysulfones