Efficient and regioselective synthesis of bicyclic pyrrolidones or bicyclic pyridones by cyclocondensation of heterocyclic ketene aminals with nitro-phenylpropiolate

Abstract

Heterocyclic ketene aminals (HKAs) underwent nucleophilic addition to the α, β-unsaturated CC of nitro-phenylpropiolate, obtaining a series of novel bicyclic pyrrolidones or bicyclic pyridones, whereas the opposite regioselectivity was observed for direct addition of HKAs to the β-C-position or α-C-position of the unsaturated ester; furthermore, this unprecedented nitro-substituted position regulated reactivity was validated by means of Density Functional Theory (DFT) calculations.