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

Abstract

The 9,10-dicyanoanthracene-photosensitized (DCA-photosensitized) electron-transfer 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.