UC San Diego

As a powerful alternative to transition metal-based desulfurization reactions, P(III) reagent-mediated radical desulfurization processes have been demonstrated to desulfurize alkyl thiols at high efficiency and good functional group tolerance. This process generates carbon-centered radicals derived from the thiol reagent and creates a variety of possibilities to forge novel carbon-carbon and carbon-heteroatom bonds. There is a strong incentive to expand this powerful reactivity to aryl thiols as a potential new method of aryl carbon coupling reactions. However, conclusions from previous studies suggested the limitation of this method in generating aryl radicals. Inspired by previous mechanistic studies from the Schmidt Group, I established a set of optimized conditions for the radical desulfurization of aryl thiols using a class of P(III) reagents—phosphinites. Based on mechanistic experiments, I revised the previously proposed mechanism of the SAT process. Additionally, I demonstrated that a competing substitution pathway was polar, and proposed a mechanism for this pathway.