Formal [3+2] Cycloaddition Reactions of Electron-Rich Aryl Epoxides with Alkenes under Lewis Acid Catalysis Affording Tetrasubstituted Tetrahydrofurans.

Víctor E Macías-Villamizar,Santiago Rodríguez,Florenci V González,Luís Cuca-Suárez

doi:10.3390/molecules25030692

Abstract

We report on the regio- and stereoselective synthesis of tetrahydrofurans by reaction between epoxides and alkenes in the presence of a Lewis acid. This is an unprecedented formal [3+2] cycloaddition reaction between an epoxide and an alkene. The chemical reaction represents a very concise synthesis of tetrahydrofurans from accessible starting compounds.

Highlights

Diaryl dimethyltetrahydrofurans lignans (Figure 1) are an important group of natural products displaying anti-apoptotic, anticancer, and anti-inflammatory properties [1,2,3] and interesting new examples have been found during the last few years [4]
Some interesting examples have been recently reported, for example, the combination of allylic silanes and aldehydes in the presence of a Lewis acid [7], the reaction between ketenes and vinyl cyclopropanes under palladium catalysis [8] or the cycloaddition between a palladium-oxyallyl complex and a diene [9]
We report the preparation of tetrahydrofurans by (B)

Summary

Introduction

Diaryl dimethyltetrahydrofurans lignans (Figure 1) are an important group of natural products displaying anti-apoptotic, anticancer, and anti-inflammatory properties [1,2,3] and interesting new examples have been found during the last few years [4]. Formal [3+2] cycloadditions represent an interesting synthetic approach for the preparation of tetrahydrofurans. Some interesting examples have been recently reported, for example, the combination of allylic silanes and aldehydes in the presence of a Lewis acid [7], the reaction between ketenes and vinyl cyclopropanes under palladium catalysis [8] or the cycloaddition between a palladium-oxyallyl complex and a diene [9]. Cascade cyclizations of polyepoxides stand as one of the most beautiful and efficient reactions in organic synthesis [12]. In some of these intramolecular reactions, an alkene is the initiating nucleophile that attacks the first epoxide which will trigger the process

Methods

Results

Conclusion