Generation of 1,3-Dimethylene-Substituted Isobenzofurans via Pd(II)-Catalyzed Selective Oxo-cyclization/SO2 Insertion Cascade of β-Alkynyl Ketones

Article abstract of DOI:10.1021/acs.joc.8b02934

A new palladium(II)-catalyzed cyclization-radical addition cascade enables the direct construction of 1,3-dimethylene-substituted isobenzofuran derivatives containing a vinyl aryl sulfone unit in good yields by treating with β-alkynyl ketones, aryl diazonium salts, and DABCO·(SO₂)₂. The oxidant-free multicomponent reaction features good substrate scope and functional group tolerance, which proceeds through a sequence of Heck coupling, oxo-cyclization, and SO₂ insertion.