4-addition reactions of alkanesulfonamides were developed on the ‘product base’ strategy. Alkanesulfonamides reacted with α,β-unsaturatedamides in good to high yields with good to high diastereo- and enantioselectivities using a chiral alkaline metal amide. To our knowledge, this is the first example of a catalytic asymmetric C–C bond-forming reaction using an alkanesulfonamide without any activating group