A Room-Temperature-Stable Phosphanorcaradiene.

A room-temperature-stable crystalline phosphanorcaradiene 2 has been synthesized via a C-C bond forming strategy induced by the demetalation of a phosphepine-Au complex 1 using a Lewis base (Ph3P, IDipp or CyNC). Compound 2 undergoes photolysis to afford a 2 H-phosphirene 4. Ru(PPh3)3Cl2 is shown to catalyze the equilibration of 2 and 4 in solution. In addition, the transformation of 2 to 4 can be achieved by a two-step strategy, namely cyclopropenylidene-induced ring opening to give cyclopropenylidene-stabilized vinylphosphinidene 7 followed by elimination of cyclopropenylidene by an electrophile including TMSOTf and Me2SBH3.