An unexpected course in the 6-exo radical cyclizations of trichloroacetamides on changing the N-substituent from benzyl to α-methylbenzyl

Abstract

Radical cyclization of N-(α-methyl)benzyl substituted trichloroacetamides upon α,β-unsaturated nitriles has been studied. Tributyltin hydride treatment of trichloroacetamides 5a and 5b gives morphan derivatives (1 and 2), through a 6-exo-trig radical cyclization, and unexpectedly normorphans 6 and 7 as a result of a stereoespecific process in which the stereogenic benzylic carbon undergoes a configurational inversion.