The regio- and stereoselectivity in the solvomercuriation and intramolecular alkoxymercuriation of several cyclic olefinic alcohols were examined. The regioselectivity is controlled mainly by electronic factors, while the stereoselectivity is controlled by steric factors as well as electronic ones. The optimised structure of the mercurinium ion intermediate suggests that the attractive interaction between the hydroxy group in the molecule and the mercurinium ion moiety affects the selectivity.
FeSO4/CuCl2 yielded 1-(1-chlorocyclohexyl)ethanone as the major product consistent with 6-endo-trig cyclization of the intermediate 5-acetylhex-5-enyl radical. This strategy was extended to the ring enlargement of a series of 1-isopropenylcycloalkyl hydroperoxides. Regioselective 7- or 8-endo-trig cyclizationreactions could be achieved by treatment of the corresponding cyclopentyl or cyclohexyl hydroperoxides