Regiospecific oxidative cyclization of n-methylsulfonylamines into pyrrolidines

Abstract

In the framework of the approach to remote oxidative functionalization of organic compounds of various classes, which is currently under exploration by us and which is based on reactions of element-centred free radicals, the regiospecific oxidative cyclization of N-methylsulfonylalkylamines 3 into N-methylsulfonylpyrrolidines 4 has been accomplished. The more facile isomerisation of intermediate sulfonamidyl radicals 8 with 1,5-H shift in comparison with their carboxamidyl analogues 16 is, in our opinion, the chemical proof of different electronic configurations of radicals 8 (σ structure) and 16 (predominantly π structure) generated under identical conditions using Na 2S 2O 8CuCl 2 system.