A new class of organocatalyst has been developed that incorporates a sulfinyl group as a urea or thiourea substituent. The sulfinyl group serves to simultaneously acidify the urea and provide asymmetric induction in hydrogen-bond-catalyzed reactions. The utility of this new catalyst structure is demonstrated by the high selectivity provided in the aza-Henry reaction not only for aromatic N-Boc imine substrates but also for aliphatic imines for which enantioselective H-bonding catalysis has not previously been demonstrated.