Benzannulation and N‐Annulation of β‐Ketoenamines for Synthesizing Aniline and Pyridine Derivatives Using DMSO as a Methine Source

Abstract

AbstractBenzannulation and N‐annulation of β‐ketoenamines by the in‐situ generated methyl(methylene)sulfonium ion from the reaction of dimethyl sulfoxide (DMSO) and 1,2‐dibromoethane (DBE) was achieved. The β‐ketoenamines underwent N‐annulation to pyridine derivatives, while the N‐alkylated enamines were benzannulated to afford substituted anilines. The utility of the intermediate methyl(methylene)sulfonium ion was further extended for synthesizing methylene‐bridged bis‐1,3‐dicarbonyl compounds.magnified image