Metal-free synthesis of phosphinoylchroman-4-ones via a radical phosphinoylation-cyclization cascade mediated by KSO.

A variety of chroman-4-ones bearing phosphine oxide motifs were conveniently synthesized from readily available diphenylphosphine oxides and alkenyl aldehydes via a metal-free tandem phosphinoylation/cyclization protocol. The reaction utilizes KSO as oxidant and proceeds in DMSO/HO at environmentally benign conditions with a broad substrate scope and afforded the title compounds in moderate yields.