The reduction of radical 5 to the organosamarium(II) species 7 is very likely to be too slow a process to kinetically compete with the very fast (see Ref. 8) radical ring closing process leading from 5 to 6. Competition between (slower) radical cyclisation of primary radicals onto unsubstituted terminal double bond according to the 5-exo-trig mode and their trapping by SmI 2 in THF has been studied by Curran and co-worker (Hasegawa, E.; Curran, DP Tetrahedron ...