Manganese- and Rhodium-Catalyzed Phenylsilane Hydrosilation−Deoxygenation of Iron Acyl Complexes Cp(L)(CO)FeC(O)R (L = CO, PPh3, P(OMe)3, P(OPh)3; R = CH3, Ph, CHMe2, CMe3)
Autor: | Alan R. Cutler, Zhibiao Mao, and Brian T. Gregg |
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Rok vydání: | 1998 |
Předmět: | |
Zdroj: | Organometallics. 17:1993-2002 |
ISSN: | 1520-6041 0276-7333 |
DOI: | 10.1021/om970659m |
Popis: | The manganese carbonyl acyl complexes L(CO)4MnC(O)R (L = CO, R = CH3 (2a); L = CO, R = Ph (2b); L = PPh3, R = CH3 (2c)) are precatalysts for the PhSiH3 hydrosilation−deoxygenation of Cp(CO)2FeC(O)CH3 (1a) to Cp(CO)2FeCH2CH3 (6a). Thus, 2a (4%) and 1.1 equiv of PhSiH3 reduce 1a initially to a mixture of [Cp(CO)2FeCH(CH3)O]3-xHxSiPh (x = 2 (3b), 1 (4b), and 0 (5b)) (7−8 h), which transforms to a mixture of 5b (62%) and 6a (35%) (12 h). Similarly, 2b and PhSiH3 transform 1a to a mixture containing 4% 3b, 22% 4b, 72% 5b, and 2% 6a (30 min), then up to 15−20% 6a (12 h). Use of 2c as the precatalyst selectively yields 71% 4b and 10% 6a (30 min), then up to 19% 6a (5 h). Both 4b and 5b were isolated by size-exclusion chromatography and characterized as mixtures of four stereoisomers, 4b as a pair of enantiomers having a prochiral center and two meso diastereoisomers with pseudoasymmetric centers and 5b as a diastereomeric pair of enantiomers. The PhSiH3 (1.6 equiv)/RhCl(PPh3)3 (3%) system conveniently transforms... |
Databáze: | OpenAIRE |
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