Sustainable Thioester Derivatives Synthesis via TBADT-Photocatalyzed Continuous Hydrogenacylation of Aldehydes and Isothiocyanates

Abstract

Thioesters serve as indispensable pharmacophores and versatile functional building blocks, finding broad utility in pharmaceutical development, prodrug design, and functional material synthesis owing to their unique chemical reactivity, metabolic stability, and target-binding affinity; however, conventional thioester synthesis is plagued by critical limitations: reliance on toxic sulfur precursors, harsh reaction conditions, costly metal catalysts, and environmentally detrimental byproducts—factors impeding large-scale, sustainable manufacturing. Herein, we report a green and efficient protocol for thioester synthesis via TBADT-photocatalyzed sequential continuous hydrogenacylation of aldehydes with isothiocyanates, mechanistic studies showing this transformation proceeds via a radical cascade reaction enabled by photoinduced multi-step Hydrogen Atom Transfer (HAT) processes: photoexcited TBADT abstracts an aldehydic C–H H-atom to generate acyl radicals, which undergo regioselective addition to isothiocyanates, followed by HAT regeneration to afford thioesters. This protocol features notable advantages: a broad substrate scope encompassing linear/cyclic/branched alkyl aldehydes, electron-rich/deficient aryl isothiocyanates, and heteroaromatic scaffolds; water as a key co-solvent enhances reaction efficiency and sustainability, further by eliminating toxic reagents, external oxidants, and pre-functionalization steps, this work overcomes core challenges in traditional thioester synthesis, establishing a novel and sustainable platform for thioester preparation and functionalization of bioactive molecules—thus advancing green organic synthesis and pharmaceutical chemistry.

Keywords

Thioester synthesis / Visible-light photocatalysis / Novel sulfur sources / HAT catalysis / Radical addition / Isothiocyanates / Continuous hydrogenacylation / Green organic synthesis

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2026 SIOC, CAS, Shanghai, & WILEY-VCH GmbH