Visible-light Photoredox Catalyzed Giese Reaction of 1,3-Dithiane using Silicon as a Radical Precursor

Abstract

Neutral silicon is one of the promising radical precursors that is yet underdeveloped when compared to another radical precursor such as carboxylate and borate. This study presents a novel method for generation of 1,3-dithianes radical via visible-light photoredox catalyzed Giese reaction between silicon radical precursor and various Michael acceptor as a coupling partner. The developed method was conducted in mild condition, utilization of aqueous solution and showed good functional group tolerance with good to excellent yields. Based on mechanistic studies, we proposed a plausible mechanism that involves generation of 1,3 dithiane radical via single-electron oxidation of trimethylsilyl 1,3-dithiane.