Synthesis of sterically hindered enamides via a Ti-mediated condensation of amides with aldehydes and ketones

摘要

The first TiCl_4-mediated condensation of secondary amides with aldehydes and ketones has been achieved. The reaction proceeds at room temperature and is complete within 5 h in most cases. The optimized procedure used 5 equiv of an amine base hinting that the in situ activation of both the amide and the Lewis acid is required. The reaction affords polysubstituted (E)-enamides.