Abstract It is shown by 13 C and D labelling that the ethyl radical elimination from the molecular ion of 6-methoxy-1-hexene is a very complex process involving at least two different channels. The major channel (80%) is induced by an initial 1, 5-hydrogen shift in the molecular ion from C (5) to C (l) leading via a series of steps to methoxy-cyclohexnne, which then undergoes a ring contraction to 2-methyl-1-methoxycyclopentane, being the ...
