Synthesis of 2-tetrazolyl azetidines and their evaluation in organocatalysis

A library of stereodefined 2-tetrazolyl azetidines has been synthesized starting from readily available enantiopure amino alcohols. This library was then screened to assess catalytic activity in a benchmark asymmetric aldol reaction between 4-nitrobenzaldehyde and acetone. The azetidine derived from (1S,2R)-(+)-norephedrine exhibited the best balance between good reactivity and a high level of enantioselectivity in this reaction.