Catalytic carbon–sulfur bond formation by amphoteric vanadyl triflate: exploring with thia-Michael addition, thioacetalization, and transthioacetalization reactions

A series of thiols have been examined as protic nucleophiles for Michael-type additions to α,β-unsaturated carbonyls as well as double nucleophilic condensations with aldehydes, ketones, and acetals catalyzed by amphoteric, water-tolerant vanadyl triflate under mild and neutral conditions. The newly developed C–S bond formation protocols were carried out smoothly in good to high yields in a highly chemoselective manner.