An eleven-membered macrocyclic bromomethyldimethylsilyl propargylic ether h
as been prepared in order to examine the regioselectivity of a transannular
radical process. The vinyl radical intermediate appeared to follow exclusi
vely a 6-(pi -endo)endo-trig/7-(pi -exo)exo-trig transcyclization course to
create a 6,7-bicyclic skeleton.