Manganese carbonyl complexes as catalysts for the hydrosilation of ketones: Comparison with RhCl(PPh{sub 3}){sub 3}
- Rensselaer Polytechnic Inst., Troy, NY (United States)
Manganese carbonyl complexes catalyze the hydrosilation of ketones with PhMe{sub 2}SiH and Ph{sub 2}SiH{sub 2} in C{sub 6}D{sub 6} solutions. Efficacy of the manganese carbonyl precatalysts (2.4 mol %) toward acetone hydrosilation with 1.1 equiv of PhMe{sub 2}SiH to give (CH{sub 3}){sub 2}CH(OSiMe{sub 2}Ph) (3) varied: (PPh{sub 3})(CO){sub 4}MnC(O)CH{sub 3} (1) (<5 min) > (CO){sub 5}MnC(O)Ph > (CO){sub 5}MnC(O)CH{sub 3} > (CO){sub 5}MnCH{sub 3} > (CO){sub 5}MnBr (6.0 h) > Mn{sub 2}(CO){sub 10} = (PPh{sub 3})(CO){sub 4}MnBr = (CO){sub 5}MnSiMe{sub 2}Ph (2). A turnover frequency of 27 min{sub -1} was measured for catalysis using 1% 1; rapid catalysis was possible with 0.1% 1 in the absence of solvent. As a precatalyst, 1 is much more reactive than Rh(PPh{sub 3}){sub 3}Cl for the PhMe{sub 2}SiH hydrosilation of acetone, acetophenone, and cyclohexanone; both catalysts exhibit similar reactivity with Ph{sub 2}SiH{sub 2}. With 1 as the precatalyst, isolated yields of the alkoxydimethylphenylsilanes exceeded 90%, with no evidence of competing dehydrogenative silation to yield vinyl silyl ethers. Photochemical activation of (CO){sub 5}MnSiMe{sub 2}Ph (2) affords moderate hydrosilation catalytic activity in transforming acetone to 3. In contrast, (CO){sub 4}CoSiMe{sub 2}Ph (10) or Co{sub 2}(CO){sub 8} in the presence of the excess HSiMe{sub 2}Ph, with or without photochemical activation, were ineffective acetone hydrosilation catalysts. 32 refs., 2 tabs.
- OSTI ID:
- 263128
- Journal Information:
- Organometallics, Vol. 15, Issue 12; Other Information: PBD: 11 Jun 1996
- Country of Publication:
- United States
- Language:
- English
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