Bimolecular Photoreduction of Aromatic Sulfoxides

Abstract

Photolysis of aromatic sulfoxides in the presence of alkoxides in alcoholic solvents provides a photochemical route to the corresponding sulfides. Other electron donors also give sulfide with various degrees of success. The reaction could also be carried out using carbazoles as sensitizers, and quantitative yields could be obtained using N-methylcarbazole in methanol. Evidence points toward a hydroxysulfuranyl radical as the key intermediate, and solvent effects point to heterolysis, rather than homolysis, as the step that breaks the S-O bond.

Photochemistry of Substituted Dibenzothiophene Oxides: The Effect of Trapping Groups1

“…This idea has precedent, for example, in -phenylvalerophenone, which is a uniquely unreactive phenyl ketone toward internal hydrogen abstraction. 43 In analogy to that example, the mechanism for quenching by the side chain of 2d is most likely reversible charge transfer from the side chain sulfur to the easily reduced 44 DBTO nucleus. An alternative interpretive framework with substantial merit has been offered by a referee.…”

Photochemistry of thiophene‐S‐oxide derivatives

“…This may be mechanistically related to the observation of electron-transfersensitized photoreductions of a number of sulfoxides. [24,25] 'Benzyl' functionalization Thiemann examined a series of TO derivatives that contained methyl groups in the 2 and 5 positions. In the absence of hydroxylic solvent, the thienyl alcohol and/or thienyl ether is observed as part of the product mixture; ethanol was used to form the ethyl thienyl ether in at least one case.…”

A Facile and Efficient Iron‐Catalyzed Reduction of Sulfoxides to Sulfides

“…However, no negative effect was observed on the yield of product 7 a, hence a radical-based mechanism could be excluded. [11] 1 H NMR spectroscopic analysis of the reduction of 7 to 7 a with PhSiH 3 in C 6 D 6 , using the para-methyl group as a probe, detected only the decrease in amounts of 7 and the increase in amounts of 7 a, whereas no intermediates were detected on the NMR timescale. Moreover, no signal was found for an iron hydride species.…”