Organocatalytic enantioselective synthesis of ß-amino sulfonic acid derivatives.

An unprecedented enantioselective conjugate addition reaction of sodium bisulfite to various nitrostyrenes occurred upon the influence of a bifunctional amino-thiourea organocatalyst; a strategy that opens a straightforward route to unprotected chiral taurine derivatives thanks to the reduction of the obtained ß-nitroethanesulfonic acids into the corresponding amino derivatives.