Cross-Electrophile Sulfonylation Involving Morita–Baylis–Hillman Acetates and Alkyl Halides: Access to Allyl–Alkyl Sulfones

A transition-metal-, photocatalyst-, and light-irradiation-free cross-electrophile sulfonylative method has been developed. This approach, which even avoids metal reductants, such as Zn or Mn, leverages readily available Morita-Baylis-Hillman (MBH) acetates and alkyl halides. The core of this methodology is the dual action of sodium dithionite (Na₂S₂O₄), which transforms electrophilic alkyl halides into nucleophilic alkyl sulfinates through single-electron reduction and SO₂ incorporation. This robust and general route enables the synthesis of allyl-alkyl sulfones with high chemo-, regio-, and stereoselectivities, demonstrating broad substrate generality, including pharmaceutically relevant compounds.