General electron–donor–acceptor complex mediated thioesterification reaction via site-selective C–H functionalization using aryl sulfonium Salts†

Contemporary methods for synthesizing thioesters often necessitate expensive catalysts and harsh conditions, making their synthesis from chemical feedstocks challenging. Herein, we report a sustainable metal-, photocatalyst-, and oxidant-free electron donor–acceptor (EDA) mediated synthesis of thioesters via site-selective C–H functionalization using aryl sulfonium salts (acceptor) with potassium thioacid salts (donor) under visible light irradiation. Our approach enables rapid access to thioesters from a wide variety of arenes, including pharmaceutical and agrochemical compounds, as well as a diverse range of alkyl, aryl, and heteroaryl potassium thioacid salts with excellent efficiency and regioselectivity. Mechanistic studies supported the formation of an EDA-complex, and radical trapping experiments corroborated the involvement of a radical-based mechanism for the product formation. Moreover, our method demonstrates excellent atom economy and E-factor scores, which are considered excellent in terms of safety, economic and ecological yardsticks.