Asymmetric Hydrosilylation of 1-Alkenes Catalyzed by Palladium–MOP

Abstract

Abstract Asymmetric hydrosilylation of simple terminal alkenes (RCH=CH2) with trichlorosilane at 40 °C in the presence of 1 × 10−3 or 1 × 10−4 molar amounts of palladium catalyst prepared in situ from [PdCl(η3-C3H5)]2 and (S)-2-diphenylphosphino-2′-methoxy-1,1′-binaphthyl ((S)-MeO-MOP) proceeded with unusual regioselectivity and with high enantioselectivity to give high yields of 2-(trichlorosilyl)alkanes together with a minor amount of 1-(trichlorosilyl)alkanes. Optically active alcohols, RCH(OH)CH3, were obtained by oxidation of the carbon–silicon bond. Regioselectivities for forming 2-silylalkanes over 1-silylalkanes and enantiomeric purities of alcohols are as follows: R = n-C4H9: 89/11, 94% ee (R). R = n-C6H13: 93/7 95% ee (R). R = n-C10H21: 94/6, 95% ee (R). R = PhCH2CH2: 81/19, 97% ee (S). R = PhCH2CH2CH2: 80/20, 92% ee (R). R = cyclo-C6H11: 66/34, 96% ee (R). A similar hydrosilylation of 1-alkenes, 4-pentenyl benzoate and 1,5-heptadiene gave corresponding 2-alkanols of 90% ee and 87% ee, respectively, the ester carbonyl and the internal double bond remaining intact.