Insertion of Organic Carbonyls into the Tantalum-Silicon Bond of (Eta 5-C5Me5)Cl3TaSiMe3. Preparation and Characterization of the Alpha-Silylalkoxides (Eta 5-C5Me5)Cl3TaOCRR'SiMe3

摘要

Organic carbonyl compounds O=CRR (R,R = H, H; Me, H; Me, Me; Ph, H; Ph, Me; - (CH2)5; CH=CH2, H; CH=CH2, Me) react with Cp Cl3TaSiMe3(1, Cp = n5-C5Me5) to give the a-silylalkoxide insertion products Cp Cl3TaOCRR SiMe3 (2a-h). In contrast, reaction of 1 with benzophenone yields Me3SiCl presumably via a reductive elimination pathway. Kinetic data for the insertion reactions are consistent with a second-order rate law, rate = k(1)(carbonyl). Hydrolyses of 2a, 2b and 2h produce the corresponding alpha silylalchohols HOCRR SiMe3. The insertion of dipheyldiazomethane into the Ta-Si bond of 1 leads to the orange complex Cp Cl3Ta(N2-N(SiMe3)NCPh2)(3). Keywords: Carbonyl compounds, Alcohols.