Synthesis of Substituted Morpholines Using Stereodivergent Aza-Michael Reactions Catalyzed by Bronsted Acids

A diastereoselective intramolecular aza-Michael reaction between N-Cbz carbamates and enones was studied. The investigation revealed that Bronsted acids with different strengths produce different diastereomers. The catalysts TfOH and TFA were used to generate differential outcomes in the aza-Michael reaction.