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 K2S2O8 as oxidant and proceeds in DMSO/H2O at environmentally benign conditions with a broad substrate scope and afforded the title compounds in moderate yields.
A photoelectrochemical cell is able to save nearly 90% external bias input to realize activation of P–H/C–H bonds for cross-coupling hydrogen evolution as compared with an electrochemical cell.