Generation of 1,3-dimethylene-substituted isobenzofurans via Pd(II)-catalyzed selective oxo-cyclization/SO₂ insertion cascade of β-alkynyl ketones

Shuai Liu, Ke Chen, Wen-Juan Hao,* Xing-Chao Tu, Shu-Jiang Tu, Bo Jiang*

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

J. Org. Chem. 2019, 84, 1964-1971