Dearomative (3 + 2) Cycloaddition of Indoles for the Stereoselective Assembly of Fully Functionalized Cyclopentanoids

Org Lett. 2024 May 17;26(19):4077-4081. doi: 10.1021/acs.orglett.4c01139. Epub 2024 May 2.

Abstract

The gold(I)-catalyzed dearomative cyclopentannulation of various indoles with 2-ethynyl-1,3-dithiolane is reported. The method generates three new stereocenters with excellent control of relative stereochemistry and is tolerant of diverse functionalization and substitution patterns on the indoles. The obtained cyclopentane-fused indolines allow for interesting subsequent synthetic manipulations, giving rise to fully substituted cyclopentanes with control of the relative stereochemistry of all five stereocenters. The reported reaction illustrates and elucidates a mechanistic dichotomy underlying gold(I)-catalyzed reactions of 2-ethynyl-1,3-dithiolane.