Highly Diastereoselective Synthesis of (3R, 4R)- and (3R, 4S)-β, γ-Diamino Acids from D-Phenylalanine

Abstract

(2R, 3S)-N-Boc-2-Amino-3-hydroxy-1-phenylbutane (9a) and (2R, 3S)-N-Boc-2-amino-3-hydroxy-1-phenylpentane (9b) were converted to (3R, 4R)-N³-Boc-3, 4-diaminopentanoic acid (12a) and (3R, 4R)-N³-Boc-3, 4-diaminohexanoic acid (12b) through SN2 type substitution of the hydroxy group to an amino group and oxidation of the phenyl group to a carboxyl group. In a similar way, the (3R, 4S)-isomers (18a, b) were also synthesized from (2R, 3R)-N-Boc-2-amino-3-hydroxy-1-phenylbutane (15a) and (2R, 3R)-N-Boc-2-amino-3-hydroxy-1-phenylpentane (15b), respectively, derived from (2R, 3S)-N-Cbz-2-amino-3-hydroxy-1-phenylbutane (6a) and (2R, 3S)-N-Cbz-2-amino-3-hydroxy-1-phenylpentane (6b) by means of the diastereoconversion reaction.