The chromous chloride promoted addition of N-haloamides to olefins. IV. Mechanistic aspects

A discussion on the mechanism of the chromous chloride promoted addition of N-haloamides to olefins is presented on the basis of the results already reported and some additional evidence. The mechanism proposed involves a radical chain addition in which the N-haloamide acts as the transfer agent, the termination steps being chromium(II) reduction of the amido radical and chromium(II) reduction of the intermediate adduct radical. The addition of N-chloro- and N-bromoacetamide to norbornadiene is described. The use of chromous chloride to initiate the reaction of N-chloropiperidine with ethyl vinyl ether and cyclohexene led to low yields of addition.