Abstract Treatment of α-alkyl and α, α-dialkyl homoallylic amines 1 with PhSeX (X= Cl, Br, I), in CH 3 CN containing sodium carbonate produced mixtures of azetidines 2 and pyrrolidines 3. The cyclization also occurred in the absence of Na 2 CO 3, and the corresponding azetidinium and pyrrolidinium salts 2 (HX) and 3 (HX) were formed in CDCl 3 or CH 3 CN. The crude reaction mixtures were analysed by 77 Se NMR. Each product− 2, 3, 2 (HX), ...