12. N,N'-Carbonyldiimidazole-Mediated Cyclization of Amino Alcohols to Substituted Azetidines and Other N-Heterocycles
R. M. de Figueiredo, R. Fröhlich, M. Christmann
Amino alcohols are important synthons for N-heterocycles. We have developed an efficient method to activate hydroxyl groups, which avoids the use of toxic reagents and tolerates a wide variety of functional groups. Our strategy has been applied to the synthesis of functionalized p-methoxyphenyl-protected azetidines, pyrrolidines, and piperidines. The required amino alcohols were synthesized according to an optimized proline-catalyzed Mannich protocol. An azetidine analogue of ezetimibe was synthesized to demonstrate the potential for the synthesis of drug-like molecules.