Arbuzov-Like Reaction in the Trimethyl Phosphite-Eta2-Silaacyl Adduct (Eta5-C5Me5)Cl3Ta(Eta2-OC(SiMe3)(P(OMe)3))

摘要

Our studies concerning the carbonylation chemistry of early transition metal silyl complexes have led to the discovery of Cp*C1 Ta (n-COSiMe) (1,Cp* =n -C Me), a reative n silaacyl derivative. Recently we have found that 1 readily reacts with Lewis bases to form complexe: of the type Cp*C1 Ta OC(L)SiMe, in which the Lewis donor binds to the silaaclycarbon atom. Here we report the preparation and characterization of the trimethyl phosphite adduct Cp*C1 Ta n -OC(SiMe)P(OMe) (2) and its spontaneous Arbuzov-like dealkylation to MeC1 and Cp*C1 TaN-OC(SiMe)P(OMe)O (6). The latter compound, which has been characterized by X-ray crystallography, contains an unusual n-phosphonatosilaacy (2-) ligand. The dealkylation of trialkyl phosphites is promoted by a number of transition metal complexes. Dealkylation is usually preceded by coordination of phosphite to the transition metal. In a few cases this process appears to follow attack of the phosphite onto an electrophitic ligand bound to metal, as in the reaction reported here.