Asymmetric Synthesis of Organosilicon Compounds Using a C2 Chiral Auxiliary

Article abstract of DOI:10.1246/bcsj.70.1393

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 of the other optical silanes is also described. The maximum rotations of some of them have been determined by ¹H NMR and/or capillary GC methods. A mechanism for a diastereoselective ring-opening reaction is proposed based on the stereochemical results.