N-Tosylimidates in highly enantioselective organocatalytic Michael reactions

N-Tosylimidates acted as nucleophiles in highly enantioselective organocatalytic Michael addition reactions to α,β-unsaturated aldehydes in the presence of a catalytic amount of trialkylsilyl-protected diarylprolinol. In particular, α-phenyl-substituted N-tosylimidates showed good reactivity. We also demonstrate that the kinetic acidity of the α-proton of α-phenyl N-tosylimidate as measured by proton/deuterium NMR exchange experiments is correlated with the potential of N-tosylimidates to act as nucleophiles in organocatalytic reactions.