Deoxygenation and Other Photochemical Reactions of Aromatic Selenoxides1

Atomic oxygen O(3P) is a potent oxidant that has been well-studied in the gas phase. However, exploration of its reactivity in the condensed organic phase has been hampered by the lack of an appropriate source. Dibenzothiophene-S-oxide (DBTO) and related derivatives have been promoted as photochemical O(3P) sources but suffer from low quantum yields. Photolysis of dibenzoselenophene-Se-oxide (DBSeO) results in the formation of dibenzoselenophene and oxidized solvent in significantly higher quantum yields, ca. 0.1. The oxidation product ratios from toluene obtained from the photolysis of dibenzothiophene-S-oxide and the corresponding selenoxide are the same, strongly suggesting a common oxidizing intermediate, which is taken to be O(3P). An additional product, proposed to be the corresponding selenenic ester, is also observed under deoxygenated conditions. The photochemistry of diphenyl selenoxide includes a minor portion of oxidantforming deoxygenation, in contrast to previous conclusions (Yamazaki, Y.; Tsuchiya, T.; Hasegawa, T.Bull. Chem. Soc. Jpn. 2003, 201−202). Disciplines Chemistry | Organic Chemistry | Other Chemistry | Polymer Chemistry Comments Reprinted (adapted) with permission from Journal of the American Chemical Society; 126(49); 16058-16065. Doi: 10.1021/ja045935k. Copyright 2004 American Chemical Society. Rights One-time permission is granted only for the use specified in your request. No additional uses are granted (such as derivative works or other editions). For any other uses, please submit a new request. This article is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/chem_pubs/162 Deoxygenation and Other Photochemical Reactions of Aromatic Selenoxides1 Ryan D. McCulla and William S. Jenks* Contribution from the Department of Chemistry, Iowa State UniVersity, Ames, Iowa 50011-3111 Received July 7, 2004; E-mail: [email protected] Abstract: Atomic oxygen O(3P) is a potent oxidant that has been well-studied in the gas phase. However, Atomic oxygen O(3P) is a potent oxidant that has been well-studied in the gas phase. However, exploration of its reactivity in the condensed organic phase has been hampered by the lack of an appropriate source. Dibenzothiophene-S-oxide (DBTO) and related derivatives have been promoted as photochemical O(3P) sources but suffer from low quantum yields. Photolysis of dibenzoselenophene-Se-oxide (DBSeO) results in the formation of dibenzoselenophene and oxidized solvent in significantly higher quantum yields, ca. 0.1. The oxidation product ratios from toluene obtained from the photolysis of dibenzothiophene-Soxide and the corresponding selenoxide are the same, strongly suggesting a common oxidizing intermediate, which is taken to be O(3P). An additional product, proposed to be the corresponding selenenic ester, is also observed under deoxygenated conditions. The photochemistry of diphenyl selenoxide includes a minor portion of oxidant-forming deoxygenation, in contrast to previous conclusions (Yamazaki, Y.; Tsuchiya, T.; Hasegawa, T. Bull. Chem. Soc. Jpn. 2003, 201-202).