Asymmetric .ALPHA.-substituted phenethylamines. II. The enantioselective synthesis of 1-aryl-2-phenylethylamines from L- and D-amino acids by means of 1,3-asymmetric induction.

Abstract

Optically pure (1S, 1'S)-1-aryl-N-(1'-alkyl-2'-hydroxyethyl)-2-phenylethylamines (13-21) were synthesized from L-alanine, L-leucine, and L-isoleucine via (S)-2-aminoalkanols (1-3) and (E)-(S)-N-(1-alkyl-2-hydroxyethyl) arylmethylideneamines (4-12). On the other hand, the amines with (1R, 1'R) configuration (33-38) were synthesized from D-amino acids, i.e., D-alanine and D-leucine. The absolute configurations of these amines were confirmed by the aromatic quadrant-sector rule. The asymmetric reactions of chiral azomethines (7-12 and 30-32) with benzylmagnesium chloride were found to be extremely highly stereoselective. However, the reactions of the azomethines (4-6 and 27-29) derived from L- and D-alanine with the Grignard reagent afforded poor stereoselectivity.