Palladium-Catalyzed Radical Cascade Iododifluoromethylation/Cyclization of 1,6-Enynes with Ethyl Difluoroiodoacetate.

A novel and convenient Pd-catalyzed radical cascade iododifluoromethylation/cyclization of 1,6-enynes with ethyl difluoroiodoacetate is demonstrated. The proposed transformation presents high stereoselectivity under mild and facile reaction conditions, thereby allowing an efficient access to a variety of iodine-containing difluoromethylated pyrrolidines. A possible radical pathway for the transformation is proposed on the basis of the results of control experiments and relevant literature reviews.