Homoallylic rearrangement and electron spin resonance of cyclopropylcarbinyl radicals

Free-Radical Rearrangements

“…Cyclopropylcarbinyl generated in an ESR cavity at temperatures of -140°C and below shows the expected spectrum (57,438). It is clear that 234 and 235 are discrete chemical entities and do not have a nonclassical structure.…”

“…It is clear that 234 and 235 are discrete chemical entities and do not have a nonclassical structure. The ESR spectrum of 234 indicates that the bisected conformation 236 is preferred to the perpen dicular conformation 237 (7,22,438,439,446). Between -140° and -100°C spectra for both 234 and 235 are observed, whereas above -100°C only 235 can be detected.…”

Electrochemical oxidation of trifluoroacetic acid anion. V. Formation of bis(trifluoromethyl) alicyclic compounds from activated dienes

“…The product 90 (3-exo-trig process) was also observed but in a very small amount. In fact, it is known that cyclopropylmethyl radicals have very short lifetimes and the reversed reaction to the open chain radicals is very fast (6). The small quantity of 9a detected may be attributed to a trapping of the radical 12a by a CF, radical.…”

A homoallyl radical rearrangement. Kinetics of the isomerization of the 2,2-dimethyl-3-buten-1-yl radical to the 1,1-dimethyl-3-buten-1-yl radical

“…(14,15), for the CH,=CHCH2CH2 radical, a H y = 0.6 G and at'6 (IH) = 0.35 G. Equivalence of the y-H and 6-H splittings has also been observed previously in related radlcals in the cis conformation, e.g. (16), for RCH=CHCH,CH, radicals, nt'y = a H 6 (IH) = 0.7 G (R = CH3) and = 0.61 G (R = c-C3Hs and OH).…”