Stereocontrolled Synthesis of Some Novel Azaheterocyclic β-Amino Ester Stereoisomers with Multiple Stereogenic Centers

Abstract

AbstractThe synthesis of some new functionalized azaheterocyclic β-amino esters with multiple stereocenters has been achieved from readily available unsaturated bicyclic β-amino acids by a stereocontrolled synthetic protocol involving N-allylation/propargylation, ring-opening metathesis, and selective ring closure with chemodifferentiation through ring-closing metathesis (RCM). The RCM transformation was investigated under various experimental conditions to analyze the scope of the catalyst, yield, conversion, and substrate effect. The structure of the starting (oxa)norbornene β-amino acids predetermined the structure of the new azaheterocyclic derivatives; the synthetic procedure proceeded with conservation of the configuration of the stereogenic centers.