Distinct reactivities of -chalcone-substituted organophosphines with activated alkynes: skeletal editing or periphery modification

Skeletal editing of organophosphines with cleavage of the P-C bond as the key step represents a daunting challenge due to its high dissociation energy. Herein, we report an efficient catalyst-free strategy to cleave P-Ar bonds and insert transformable propionates therein, thus achieving skeletal editing of ortho -chalcone-substituted organophosphines and the ability to generate a range of novel diphenylphosphine-oxide-substituted 2,3-dihydro-1 H -indenes with three contiguous stereocenters in a highly diastereoselective fashion. Surprisingly, replacing the propionate with an acetylenedicarboxylate or propiolamide resulted in two further distinct reaction outcomes: Acetylenedicarboxylates served as efficient dienophiles that undergo formal [4 + 2] cycloaddition with ortho -chalcone-substituted organophosphines to afford λ 5 -phosphinines, while propiolamide affords an uncommon P/N-heterocycle, benzo[ c ][1,2]azaphosphol-3-one. We report a substrate-controlled diversity-oriented synthetic strategy that can precisely convert ortho -chalcone-substituted organophosphines into other synthetically challenging organophosphorus compounds via skeletal editing or periphery modification.