Stereospecific Synthesis of gamma,delta-Diamino Esters

Abstract

gamma,delta-Diamino acid structural motifs are commonly found in bioactive molecules. We report a one-pot reaction for the synthesis of gamma,delta-diimino esters with two adjacent chiral centers in enantiomerically pure form through diaza-Cope rearrangement reaction of diimines formed from (R,R)-1,2-bis(2-hydroxyphenyl)-1,2-diaminoethane (hpen) and alde-hydes. DFT computation provides interesting insights into the stereospecific rearrangement reaction. The crystal structure of a product diimine formed from the reaction of (R,R)-hpen and 2,6-dichlorobenzaldehyde shows that the reaction gives the product diimine in S,S configuration.