330825-69-9Relevant academic research and scientific papers
Regio- and Enantioselective Hydrosilylation of 1-Arylalkenes by Use of Palladium-MOP Catalyst
Uozumi, Yasuhiro,Kitayama, Kenji,Hayashi, Tamio
, p. 2419 - 2422 (1993)
Hydrosilylation of styrenes bearing β-substituents with trichlorosilane was catalyzed by a palladium complex (0.1 mol percent) coordinated with (R)-2-methoxy-2'-diphenylphosphino-1,1'-binaphthyl ((R)-MeO-MOP) to give high yields of optically active 1-aryl-1-silylalkanes (80-85percent ee) as single regioisomers.The resulting silanes were readily converted into the corresponding optically active alcohols (80-99percent yield).
Asymmetric hydrosilylation of styrenes catalyzed by palladium-MOP complexes: Ligand modification and mechanistic studies
Hayashi,Hirate,Kitayama,Tsuji,Torii,Uozumi
, p. 1441 - 1449 (2007/10/03)
In the palladium-catalyzed asymmetric hydrosilylation of styrene (3a) with trichlorosilane, several chiral monophosphine ligands, (R)-2-diarylphosphino-1,1′-binaphthyls (2a-g), were examined for their enantioselectivity. The highest enantioselectivity was observed in the reaction with (R)-2-bis[3,5-bis(trifluoromethyl)phenyl]phosphino-1, 1′-binaphthyl (2g), which gave (S)-1-phenylethanol (5a) of 98% ee after oxidation of the hydrosilylation product, 1-phenyl-1-(trichlorosilyl)ethane (4a). The palladium complex of 2g also efficiently catalyzed the asymmetric hydrosilylation of substituted styrenes on the phenyl ring or at the β position to give the corresponding chiral benzylic alcohols of over 96% ee. Deuterium-labeling studies on the hydrosilylation of regiospecifically deuterated styrene revealed that β-hydrogen elimination from 1-phenylethyl(silyl)palladium intermediate is very fast compared with reductive elimination giving hydrosilylation product when ligand 2g is used. The reaction of o-allylstyrene (9) with trichlorosilane catalyzed by (R)-2g/Pd gave (1S,2R)-1-methyl-2-(trichlorosilylmethyl)indan (10) (91% ee) and (S)-1-(2-(propenyl)phenyl)-1-trichlorosilylethanes (11a and 11b) (95% ee). On the basis of their opposite configurations at the benzylic position, a rationale for the high enantioselectivity of ligand 2g is proposed.
