Modification of chiral monodentate phosphine ligands (MOP) for palladium-catalyzed asymmetric hydrosilylation of cyclic 1,3-dienes

Several MOP ligands 5 containing aryl groups at 2' position of (R)-2-(diphe nylphosphino)-1,1'-binaphthyl skeleton were prepared and used for palladium -catalyzed asymmetric hydrosilylation of cyclic 1,3-dienes 6 with trichloro silane. Highest enantioselectivity was observed in the reaction of 1,3-cycl opentadiene (6a) catalyzed by a palladium complex (0.25 mol %) coordinated with (R)-2-(di-phenylphosphino)-2'-(3,5-dimethyl-4-methoxyphenyl)-1,1'-bina phthyl (5f), which gave (S)-3-(trichlorosilyl)cyclopentene of 90% ee.