LAUSR

Abstract A novel synthesis of functionalized 1,2,4-triones via an oxidative homo-coupling of β-keto sulfoxonium ylides is presented. Preliminary mechanistic study reveals that the formation of the 1,2,4-trione product involves the in situ generation of an α-keto aldehyde intermediate via Cu(II)-promoted oxidative decomposition of β-keto sulfoxonium ylide followed by its coupling with the second molecule of ylide. Based on this intrinsic mechanism, a formal cross-coupling reaction was designed and successfully realized, from which more diversely functionalized 1,2,4-triones were synthesized with high efficiency. Compared with literature methods, notable features of this novel synthetic protocol include easily accessible and safe substrates, excellent functional group tolerance, convenient procedure, mild reaction conditions, and ready scalability.