The first catalytic addition reactions of sulfonylimidates have been accomplished. In the presence of a catalytic amount of DBU (normally 5-10 mol%), sulfonylimidates reacted with several N-protected imines, methyl acrylate, and azodicarboxylate to afford the corresponding addition adducts, sulfonylimidates, in excellent yields. In the addition reactions to imines, high anti-selectivity was observed. A novel direct formation of beta-amino acid derivatives from aldehyde and sulfonylimidate is also described.