Selective Transformation of 1,3‐Cyclooctadiene into Novel Functionalized Azaheterocycles, β‐Amino Esters, and Lactams by Means of Ring‐Rearrangement Metathesis

Diversity-oriented synthesis of some novel functionalized azaheterocyclic β-amino esters with multiple chiral centers from 1,3-cyclooctadiene-based β-amino acids has been accomplished through stereocontrolled metathesis protocols.

Abstract

Diversity-oriented synthesis of some novel functionalized azaheterocyclic β-amino esters with multiple chiral centers from 1,3-cyclooctadiene-based β-amino acids through a stereocontrolled synthetic route has been accomplished. The strategy was based on the creation of some novel unsaturated N-protected cyclic β-amino esters from 1,3-cyclooctadiene. Products were subjected to ring-opening metathesis (ROM) followed by selective ring-closing metathesis (RCM). A comparative investigation on the selectivity, regarding the catalysts, yields, conversions, and substrate directing effect on ring-rearrangement metathesis (RRM) transformation has been accomplished. Importantly, the procedure used in this synthetic process does not affect the configuration of the chiral centers. The pathway takes place across conservation of the configurations of the stereocenters; therefore, the architectural skeleton of the starting cyclooctene-based β-amino acids predetermined the structure of the new azaheterocyclic systems.

Zum Volltext