Oxidative Annulations Involving DMSO and Formamide: K₂S₂O₈ Mediated Syntheses of Quinolines and Pyrimidines

Abstract

An efficient strategy toward 4-arylquinolines and 4-arylpyrimidines from readily available precursors is described. Oxidative annulation promoted by K₂S₂O₈ involving anilines, aryl ketones, and DMSO as a methine (═CH-) equivalent leads to 4-arylquinolines via a cascade that entails generation of a sulfenium ion, subsequent C-N and C-C bond formations, and cyclization. The application of this strategy to the activation of acetophenone-formamide conjugates toward the synthesis of 4-arylpyrimidines is also described.