Stepwise cycloreversion of oxetane radical cations with initial C-O bond cleavage.
2,4,6-Triaryl(thia)pyrylium salts have been used as electron-transfer photosensitizers for the cycloreversion of the oxetane ring system. The radical cation of 2,3-diphenyl-4-hydroxymethyloxetane (1) undergoes stepwise splitting via initial O-C2 cleavage. Spin and charge in the resulting intermediate are located in the oxygen and carbon atoms, respectively. Subsequent intramolecular nucleophilic attack produces 2,3-diphenyl-4-hydroxytetrahydrofuran (4a). Formation of this product occurs in the submicrosecond time scale, competing with C3-C4 cleavage to the detectable (lambdamax = 470 nm) trans-stilbene radical cation.
Miranda
Miguel A
MA
Departamento de Química/Instituto de Tecnología Química UPV- CSIC, Universidad Politécnica de Valencia, Camino Vera s/n, Apdo. 22012, 46022, Valencia, Spain. mmiranda@qim.upv.es
Izquierdo
M Angeles
MA
D002412:Cations / Q000737:chemistry; D004260:DNA Repair; D004988:Ethers, Cyclic / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D010777:Photochemistry
D002412:Cations; D004988:Ethers, Cyclic; D005609:Free Radicals; C005287:oxetane