Enantioselective synthesis of (R)- and (S)-2-methyl-[3,3,2-2H3] alanines

The synthesis of optically pure (R)- and (S)-2-methyl-[3,3,3-2H3] alanines of biological interest is described. The stereochemistry of the reaction of the lithio derivative of (R)-(-)-2,5-dimethoxy-3-benzyl-3-methyl-3,6-dihydropyrazine with alkyl and deuterated alkyl iodides is discussed. The configuration of the newly formed center of chirality in (R)- and (S)-2-methyl-[3,3,3-2H3] alanines is derived from 1H NMR.