Tandem Michael addition/amino-nitrile cyclization from 2-formyl-1,4-DHP in the synthesis of novel dihydroindolizine-based compounds

A simple and efficient methodology for the synthesis of a small library of substituted indolizines with different degrees of saturation starting from the racemic 2-formyl-1,4-DHP reagent is presented. The main step of the sequential reaction was based on the highly diastereoselective tandem Michael addition/intramolecular amino-nitrile cyclization catalyzed by an organic base, which produced 1,7-dihydroindolizines in a diastereoselective manner.