Investigation of the Lewis acid mediated stereoselective cyclization of cationic aminyl radicals leading to substituted pyrrolidines

Stereoselective Lewis acid mediated radical cyclizations of variously substituted N-chloropentenylamines afforded the corresponding pyrrolidines with good to excellent diastereoselectivities and in high yields. Several Lewis acids have been screened in an attempt to find an efficient and stereoselective protocol for the formation of pyrrolidines; no apparent correlation between the different Lewis acids and the selectivities obtained was observed.