A radical cyclization route to pyrrolidines based on conjugate addition to electron deficient phenylselenenylalkenes

α-Phenylselenenyl-α,β-unsaturated esters, amides, ketones, nitriles and sulfones were prepared by zinc chloride promoted chloroselenation/dehydrochlorination of the corresponding α,β-unsaturated compounds. After Michael addition of allyl or propargylamine and triethylborane initiated reductive radical cyclization in the presence of tris(trimethylsilyl)silane, pyrrolidine and dihydropyrrole derivatives, respectively, were obtained.