Photocatalytic Chemoselective Cyclic Oxysulfonylation of 2,3-Allenoic Acids.

Photoinduced cyclization of 2,3-allenoic acids with sulfonyl chloride providing an efficient synthesis of 4-sulfonylated furan-2(5 H )-ones under mild reaction conditions has been achieved. The reaction enjoys a high chemoselectivity and tolerates a wide range of functional groups. The catalytic cycle has been validated through control experiments, cyclic voltammetry studies, and Stern-Volmer quenching studies.