Gold‐Catalyzed Reactions of 2‐Alkynyl‐1‐indolyl‐1,2‐diols with Thiols: Stereoselective Synthesis of (Z)‐α‐Indol‐3‐yl α‐(2‐Thioalkenyl) Ketones

Abstract

Propargylic glycols, 2-alkynyl-1-(indol-3-yl)-1,2-diols, react with thiols undergoing a complex but selective gold-catalyzed transformation that gives rise to α-indol-3-yl α-((Z)-2-thioalkenyl) ketones. The sequence is triggered by the regioselective thiolation of indolyl diols followed by an attack of the sulfur instead of the indole over the activated alkyne. The final compounds are obtained in remarkably high yields and arise from simple starting materials such as indolyl acyloins, ethynyl magnesium bromide and thiols.

Recent Metal-Catalyzed Methods for Thioether Synthesis

“…181 An interesting cascade transformation of propargylic glycol initiated by the hydrothiolation of the triple bond was reported in 2022. 182 The problem to convert non-activated alkenes was tackled in 2016 by Ogawa and co-workers with a simple gold(I) complex, which exhibited anti-Markovnikov selectivity (Scheme 52 ). 183 A range of terminal or cyclic (1 example) alkenes and aromatic and aliphatic thiols was successfully converted into linear thioethers.…”