Diastereoselective Acylation of Racemic Heterocyclic Amines with N-Phthaloyl and N-Naphthaloyl (S)-Amino Acyl Chlorides: Possibility of Parallel Kinetic Resolution

The acylative kinetic resolution of racemic 2-methyl-1,2,3,4-tetrahydroquinoline and 3,4-dihydro-3-methyl-2H-[1,4]benzoxazines with acyl chlorides of N-naphthaloyl-(S)-alanine and N-naphthaloyl-(S)-phenylalanine has been studied. It has been shown that diastereoselective acylation of racemic amines with N-naphthaloyl (S)-amino acyl chlorides results in the predominant formation of (R,S)-amides, whereas acylation of the same amines with N-phthaloyl (S)-amino acyl chlorides proceeds with the opposite diastereoselectivity. The parallel kinetic resolution of racemic 3,4-dihydro-3-methyl-2H-[1,4]benzoxazine using a mixture of acylating agents derived from a single precursor, (S)-phenylalanine, was carried out.