New opticallyactive organosilicon compounds such as (benzylmethylphenylsilyl)acetic acid (1) and (ethylmethylphenylsilyl)acetic acid (2) were synthesized. Application of these acids as the optical purity determining agents for chiralamines and alcohols were successfully carried out. In addition, it was also revealed that opticallyactive (benzylmethylphenylsilyl)methylamine (3) and [benzylmethyl
New optically active α-amino organosilanes, such as benzylmethylphenylsilylmethylamine, benzylmethyltolylsilylmethylamines, and anisylbenzylmethylsilylmethylamines, were obtained by the fractional crystallization of the salts of the amines and (+)-tartaric acid. Benzylmethylphenylsilylmethylamine was converted into benzylmethyl-1-naphthylphenylsilane, of which the configuration had been known. From