(CF₃CO)₂O/K₂CO₃‐Mediated Synthesis of 3‐Sulfonylchromones through Cyclocondensation of β‐Ketosulfones and Carboxylic Acids

Abstract

One‐pot (CF3CO)2O/K2CO3‐mediated tandem cyclocondensation of β‐ketosulfones with carboxylic acids provides diversified 3‐sulfonylchromones in good to excellent yields by refluxing MeCN under high‐pressure (using a sealed tube) and dry‐nitrogen atmospheric conditions. This study proposed and discussed a plausible mechanism. The paper also described the formation of 3‐sulfonylflavones and gram‐scale synthesis of 3‐sulfonylchromones. Various combinations of anhydrides and bases‐promoted reaction conditions were investigated for the (4+2) annulation via one carbon‐oxygen (C−O) bond and one carbon‐carbon (C=C) bond formations.