Diverse reactions of sterically-protected 1,3-diphosphacyclobutane-2,4-diyls with hydride.

Hydride-induced elimination of resonance stabilized substituents from a phosphorus center of 1,3-diphosphacyclobutane-2,4-diyls leads to the formation of versatile cyclic phosphaallyl anions that are useful for the construction of various electrophile-modified biradical species.

Modeling the direct activation of dihydrogen by a P2C2 cyclic biradical: formation of a cyclic bis(P-H lambda(5)-phosphorane).

The synthesis of a remarkable cyclic bis(P-H lambda(5)-phosphorane) is reported. A stable phosphorus-heterocyclic biradical, 1,3-diphosphacyclobutane-2,4-diyl, sequentially accepts negatively and positively charged hydrogen atoms to afford 2,4-diphospha-1,3-cyclobutadiene with a diylidic structure containing two P-H bonds.