Cyclization allyl benzamides

Aliphatic amine derivatives such as amides, carbamates and sulfonamides also participate in Pd - catalyzed intramolecular C-N bond formation. The relative reactivity of these amino nucleophiles toward cyclization has been evaluated in the PdCL-catalyzed cyclization of iV-protected 4-pentenylamines and 5-hexenylamines, and it was found to be urea > carbamate > tosylamide > benzamide. The PdCl2(CH3CN)2-catalyzed dehydrative cyclization of alkenyl urethanes bearing an allylic hydroxyl group has been elegantly applied to the synthesis of chiral piperidine alkaloids. The cyclization reaction occurs with complete stereocontrol in good yields in the presence of 15-20 mol % of catalyst without any reoxidant (eq 16). 

---