A Concise Synthesis of Pyrrolo- and Pyrrolidino[1,2-a]quinolin-1-ones via Diels-Alder Reactions of N-Acyliminium Cations with Olefins

Abstract

A concise and efficient synthesis of pyrrolo- and pyrrolidino[1,2-a]quinolin-l-ones has been developed. New members of this family can thus be generated via Diels-Alder reactions of olefins with N-acyliminium cations produced, in the presence of BF 3 ·Et 2 O, from 5-hydroxy-l-arylpyrrol-2-ones and 5-hydroxy-1-arylpyrrolidin-2-ones in moderate to high yields at ambient temperature.