New synthesis of 3,3-disubstituted piperidin-2-ones from esters and 1-(3-halopropyl)-2,5-dimethylpyrroles

Resumo

3,3-Disubstituted piperidin-2-ones were obtained by alkylation of carboxylic acid esters with 1-(3-halopropyl)-2,5-dimethylpyrroles using lithium diisopropylamide as a base followed by the removal of 2,5-dimethylpyrrole protection and intramolecular cyclization. The overall yields of the target products amounted to 78% in two synthetic steps.