Reactions of Arylazo Aryl Sulfones with α,β-Unsaturated Esters and Ketones Catalyzed by Palladium(O) Complex

Abstract

The palladium(0) catalyzed reactions of arylazo aryl sulfones (1) with α,β-unsaturated esters in benzene give aryl-substituted esters as major products and hydroarylated esters as minor products. The reactions of 1 with acyclic α,β-unsaturated ketones give considerable amounts of hydroarylated ketones and aryl-substituted ketones under similar conditions, whereas the reactions of 1 with cyclic α,β-unsaturated ketones afforded selectively hydroarylated compounds and no formation of aryl-substituted ketones was found. A plausible reaction mechanism is proposed.

Key Words:

• Arylazo aryl sulfones
• palladium(O) catalyst
• arylation
• α,β-unsaturated carbonyl compounds
• diarylpalladium(II) intermediate
• catalytic cycle