Asymmetric Synthesis of α-Branched Amines

　Compounds 1a and 1b are chiral auxiliary supplements and can be reacted with aldehydes or ketones to give sulfinyl imines 2. Then the addition reaction between compound 2 and a Grignard reagent¹⁾ is carried out to obtain the compounds 3 with high diastereoselectivities. The optically active amines 4 is obtained in high yields by treatment of compounds 3 with hydrochloric acid. Moreover, a convenient synthetic method of optically active β-amino acids using the compounds 1 has been reported.²⁾