Step Wise Formation of s-Alkynyl , Vinylidene, and Ninylphosphonium Complexes of Manganese( I)

J. RUIZ; R. QUESADA; M. VIVANCO; CASTELLANO, EE; OSCAR ENRIQUE PIRO

Organometallics

American Chemical Society

Año: 2005 vol. 24 p. 2542 - 2545

0276-7333

Reaction of methyl propiolate with the diphosphinomethanide complex [Mn(CO)4{(PPh2)2CH}] (1) produces simultaneously the insertion of the alkyne into the C-H bond, giving [Mn(CO)4{(PPh2)2C-C(H)dC(CO2-Me)H}] (2), and the deprotonation of the alkyne mediated by the diphosphinomethanide ligand, affording the ó-alkynyl derivative fac-[Mn(CtC-CO2Me)(CO)3(dppm)](3). Protonation of 3 with HBF4 at 200 K affords the corresponding vinylidene compound fac-[Mn(CdC(H)-CO2Me)(CO)3(dppm)]BF4 (5), which, on raising the temperature to 243 K, undergoes the spontaneous insertion of the vinylidene ligand into a Mn-P bond.