Radical ion probes. 11. Reaction of 1,1-dimethyl-5,7-di-t-butylspiro[2.5]octa-4,7-dien-6-one with 5-hexenyl magnesium bromide

In an ongoing effort to establish 1,1-dimethyl-5,7-di-t-butylspiro[2.5]octa-4,7-dien-6-one (1) as a mechanistic probe for the detection of single electron transfer (SET), the reaction of1 with 5-hexenyl magnesium bromide was examined in the hopes of observing cyclization of any intermediate 5-hexenyl radicals to cyclopentylcarbinyl radicals. A polar process dominated the reaction, but in the less prevalent SET process, the 5-hexenyl → cyclopentylcarbinyl rearrangement was extensive, indicative of freely diffusing paramagnetic intermediates