SYNTHESIS OF 2-SUBSTITUTED NITROGEN-HETEROCYCLES USING PARA-TOLUENESULFONYL IODIDE IN A KEY STEP

N-Protected aminoalkenes undergo radical addition of tosyl iodide to g ive beta-iodosulfones which can subsequently be induced to cyclise giv ing 2-substituted pyrrolidines and piperidines. Incorporation of an al pha-methylbenzyl group at nitrogen leads to a diastereoselective ring closure where the constituent diastereoisomers can be separated readil y giving chiral, non-racemic heterocycles.