Robust N-heterocyclic carbene palladium complexes are highly efficient catalysts for direct alkylsulfonylation of (hetero)aryl- or alkenyl-boronic acids with potassium metabisulfite and (hetero)alkyl-halides. Among them, acenaphthoimidazolylidene palladium(II) complexes exhibited the highest activities, and up to quantitative yields were obtained for diverse structurally distinct sulfones under very mild reaction conditions.