Optically active silanes were synthesized by a novel asymmetric synthesis which involved the diastereoselective ring-opening reaction of 1,3-dioxa-2-silacycloheptanes bearing a C2 chiral auxiliary with Grignard reagents, followed by a lithium aluminum hydride (LiAlH4) reduction. (R)-Ethylmethylphenylsilane and (R)-methylphenylpropylsilane were derived in 93%ee and 98%ee, respectively. The preparation