Three-Component Reactions of Ketene Dithioacetals, Aldehydes, and Arenesulfinic Acids: Facile Synthesis of Allylic Sulfones

Abstract

A facile and efficient synthesis of allylic sulfones via sulfuric acid–mediated three-component reactions of easily available ketene dithioacetals, aldehydes, and arenesulfinic acids is presented. The reaction features low cost and good yields.

GRAPHICAL ABSTRACT

Keywords:

• Allylic sulfones
• ketene dithioacetals
• multicomponent reactions
• sulfinic acids

Notes

^a Reaction conditions: 1a (1.0 mmol), 2a (2.0 mmol), 3a (3.0 mmol), solvent (5.0 mL), room temperature.

^b Isolated yields.

^c Stirring at 35 °C.

^d 1.2 equiv of 2a was used, and by-product A was isolated in 8% yield.

^e 2.0 equiv of 3a was used, and by-product A was isolated in 12% yield.

^f With recovery of 26% of 1a.

^g No reaction.

^h With recovery of 67% of 1a.

^a Reaction conditions: 1 (1.0 mmol), 2 (2.0 mmol), 3 (3.0 mmol), H₂SO₄ (0.5 mmol), MeCN (5.0 mL), room temperature.

^b Isolated yields.

^c By-product A was isolated in 19% yield.

^d Stirring at reflux temperature.

^e 3.0 equiv of paraformaldehyde was used.

^f TiCl₄ (1.5 mmol) used as promoter and CH₂Cl₂ as solvent.