Synthetic studies towards naturally occurring γ-(Z)/(E)-alkylidenebutenolides through bimetallic cascade cyclization and an adventitious photoisomerization method?

Organic & Biomolecular Chemistry Pub Date: 2022-03-01 DOI: 10.1039/D2OB00166G

Abstract

A general and flexible visible light-induced photoisomerization method of γ-(Z)-alkylidenebutenolides to their corresponding E-components was reported in this article. Initially, a series of naturally occurring enantiopure γ-(Z)-alkylidenebutenolides was synthesized by employing a “Pd–Cu” bimetallic cascade cyclization protocol. In the later part, the synthesized γ-(Z)-alkylidenebutenolides were photoisomerized in the presence of a triplet photosensitizer to γ-(E)-alkylidenebutenolides in reasonably acceptable yields. Total synthesis of goniobutenolides, hygrophorones, ramariolide D, melodorinols/acetyl-melodorinols, versicolactones, and phomopsolidones was achieved by employing the developed methods.

Graphical abstract: Synthetic studies towards naturally occurring γ-(Z)/(E)-alkylidenebutenolides through bimetallic cascade cyclization and an adventitious photoisomerization method
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