Photosensitized electron-transfer reactions of 1-isopropylidene-2-methylene-3,3-diphenylcyclobutane - [4+4] cycloaddition and cyclodimerization initiated by a buta-1,3-diene radical cation functionality
H. Ikeda et al., Photosensitized electron-transfer reactions of 1-isopropylidene-2-methylene-3,3-diphenylcyclobutane - [4+4] cycloaddition and cyclodimerization initiated by a buta-1,3-diene radical cation functionality, EUR J ORG C, (18), 2001, pp. 3445-3452
The 9,10-dicyanoanthracene-photosensitized (DCA-photosensitized) electron-t
ransfer reaction of 1-isopropylidene-2-methylene-3,3-diphenylcyclobutane (3
) gives a mixture of the [4 + 4] DCA adduct (5) and two [4 + 4] cyclodimers
(syn-6 and anti-6), demonstrating that 3(+) functions as a buta-1,3-diene
radical cation with its SOMO in a mainly localized state.