Synthesis of 2,5-Dihydrofurans via a Gold(I)-Catalyzed Formal [4 + 1] Cycloaddition of α-Diazoesters and Propargyl Alcohols

Org Lett. 2015 Oct 16;17(20):5124-7. doi: 10.1021/acs.orglett.5b02663. Epub 2015 Sep 28.

Abstract

A gold(I)-catalyzed formal [4 + 1] cycloaddition of α-diazoesters and propargyl alcohols is disclosed, offering access to a variety of 2,5-dihydrofurans. The reaction shows a broad substrate scope and functional group tolerance. Preliminary mechanistic investigation indicates that this reaction most likely occurs through a 5-endo-dig cyclization of an α-hydroxy allene intermediate.