A mild and highly chemoselective α-iodination of N-allylic carboxamides and lactams

Mild and highly chemoselective α-iodination reactions of N-allylic carboxamides and lactams are reported. N-Allylic amides and lactams reacted with I₂ and 2,6-lutidine at room temperature to give α-iodo amides and lactams in moderate to good yields. The exclusive α-iodination of N-allylic amides having another acidic hydrogen in the molecule proceeded under these conditions. The iodides obtained were converted to the bicyclic lactam or the β-lactam derivatives with high stereoselectivity by a radical iodine atom-transfer reaction or a nucleophilic substitution reaction.