New efficient access to fused (Het)Aryltetrahydroindolizinones via N-acyl iminium intermediates

In this paper, we described the preparation of fused (Het)Aryltetrahydroindolizinones via N-acyl iminium intermediates. Two different routes were also explored to achieve the synthesis. The first one consists in the intramolecular reaction of β-hydroxylactams whereas the second route one is an intermolecular condensation between a 2-formylester or a β-alkoxylactone and an appropriate primary amine. We also developed two heterocyclic strategies to obtain the adequate unavailable starting materials in pyridine, pyrazine, quinoline, and quinaxoline series and then perform all inter or intramolecular reactions. Scope and limitations are given.