摘要:
Reaction of methyl propiolate with the diphosphinomethanide complex [Mn(CO)(4){(PPh2)(2)CH}] (1) produces simultaneously the insertion of the alkyne into the C-H bond, giving [Mn(CO)(4){(PPh2)(2)C-C(H)=C(CO2Me)H}] (2), and the deprotonation of the alkyne mediated by the diphosphinomethanide ligand, affording the σ-alkynyl derivative fac-[Mn(C=C-CO2Me)(CO)(3)(dppm)] (3). Protonation of 3 with HBF4 at 200 K affords the corresponding vinylidene compound fac-[Mn(C=C(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.