Synthesis of allyl sulfones from potassium allyltrifluoroborates

Potassium allyltrifluoroborates underwent a bora-ene reaction with sulfur dioxide in the absence of Lewis acid catalysts to give sulfinyloxy-trifluoroborates, which subsequently undergo alkylation with electrophiles to produce sulfones in up to 91% yield. Benzyl halides and haloacetic acid derivatives can be used as the alkylation reagents while the Sanger reagent undergoes a S_NAr reaction with sulfinyloxy-trifluoroborates to produce the corresponding 2,4-dinitrophenylsulfone. The developed method allows the transformation of potassium allyltrifluoroborates into allyl sulfones.