Chemoselective Intramolecular Alkylation of the Blaise Reaction Intermediates: Tandem One-Pot Synthesis of <i>exo</i>-Cyclic Enaminoesters and Their Applications toward the Synthesis of <i>N</i>-Heterocyclic Compounds

Abstract

The intramolecular alkylative reactivity and N/C selectivity of the various Blaise reaction intermediates, which are formed from the reaction of the Reformatsky reagents with ω-chloroalkyl nitriles, did not reach the synthetic potential as an entry to <i>exo</i>-cyclic enaminoesters. To circumvent this issue, various additives were investigated, among which the addition of NaHMDS dramatically enhanced the reactivity and N/C selectivity. This modification provided a highly efficient route for the synthesis of various <i>N</i>-fused heterocyclic compounds, as it requires only two steps from nitriles