Photocatalyst-free H2O-regulated and regiodivergent multicomponent hydrogenation/bifunctional sulfonylation of alkynes

Abstract

An efficient and mild multicomponent reaction (MCR) for the preparation of vinyl sulfone is reported, which is achieved by the hydrogenation/difunctional sulfonylation of an alkynyl ester with the corresponding N-allyl bromodifluoroacetamide, DABSO and H₂O under visible light conditions without the need for any metal catalysts or additives. This transformation is the first example of a conversion using H₂O as the hydrogen source to interact with DABCO to form [DABCO-H]⁺, which ultimately reacts with the vinyl group, with the advantage of high chemoselectivity and step economy. Notably, the method produces different sulfonylation products with the same substrate regulated by the presence or absence of H₂O, which greatly reduces the cost of the chemical reaction and exhibits good functional group tolerance and substrate range. In addition, gram-scale experiments proceeded smoothly, proving the practicality of the methodology.