- Asymmetric palladium-catalyzed hydrosilylation of styrenes using efficient chiral spiro phosphoramidite ligands
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Asymmetric hydrosilylation of styrene derivatives with trichlorosilane in the presence of palladium complexes of chiral spiro phosphoramidites provided 1-aryl-1-silylalkanes as single regioisomers in high yields, which have been oxidized with hydrogen peroxide to give the corresponding chiral alcohols in up to 99.1% ee.
- Guo, Xun-Xiang,Xie, Jian-Hua,Hou, Guo-Hua,Shi, Wen-Jian,Wang, Li-Xin,Zhou, Qi-Lin
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p. 2231 - 2234
(2007/10/03)
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- Asymmetric Hydrosilylation of 1-Alkenes Catalyzed by Palladium-MOP
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Asymmetric hydrosilylation of simple terminal alkenes (RCH=CH2) with trichlorosilane at 40 deg C in the presence of 1*10-3 or 1*10-4 molar amounts of palladium catalyst prepared in situ from 3-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, 94percent ee (R).R=n-C6H13: 93/7, 95percent ee (R).R=n-C10H21: 94/6, 95percentee (R).R=PhCH2CH2: 81/19, 97percentee (S).R=PhCH2CH2CH2: 80/20, 92percent ee (R).R=cyclo-C6H11: 66/34, 96percent ee (R).A similar hydrosilylation of 1-alkenes, 4-pentenyl benzoate and 1,5-heptadiene gave corresponding 2-alkanols of 90percent ee and 87percent ee, respectively, the ester carbonyl and the internal double bond remaining intact.
- Uozumi, Yasuhiro,Kitayama, Kenji,Hayashi, Tamio,Yanagi, Kazunori,Fukuyo, Emiko
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p. 713 - 722
(2007/10/02)
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