Visible light‐induced photodeoxygenation of polycyclic selenophene Se‐oxides

Abstract

Photodeoxygenation of dibenzothiophene S‐oxide (DBTO) is believed to produce ground‐state atomic oxygen [O(3P)] in solution. Compared with other reactive oxygen species (ROS), O(3P) is a unique oxidant as it is potent and selective. Derivatives of DBTO have been used as O(3P)‐precursors to oxidize variety of molecules, including plasmid DNA, proteins, lipids, thiols, and other small organic molecules. Unfortunately, the photodeoxygenation of DBTO requires ultraviolet irradiation, which is not an ideal wavelength range for biological systems, and has a low quantum yield of approximately 0.003. In this work, benzo[b]naphtho[1,2‐d]selenophene Se‐oxide, benzo[b]naphtho[2,1‐d]selenophene Se‐oxide, dinaphtho[2,3‐b:2’,3’‐d]selenophene Se‐oxide, and perylo[1,12‐b,c,d]selenophene Se‐oxide were synthesized, and their ability to utilize visible light for generating O(3P) was interrogated. Benzo[b]naphtho[1,2‐d]selenophene Se‐oxide produces O(3P) upon irradiation centered at 420 nm. Additionally, benzo[b]naphtho[1,2‐d]selenophene Se‐oxide, benzo[b]naphtho[2,1‐d]selenophene Se‐oxide, and dinaphtho[2,3‐b:2’,3’‐d]selenophene Se‐oxide produce O(3P) when irradiated with UVA light and have quantum yields of photodeoxygenation ranging from 0.009 to 0.33. This work increases the utility of photodeoxygenation by extending the range of wavelengths that can be used to generate O(3P) in solution.

Two‐step Two‐intermediate Photorelease Bolm‐McCulla Reaction: Dual Release of Nitrene and Atomic Oxygen Reactive Intermediates

“…The system is novel in that the compound incorporates photocleavable S-N and S-O bonds for a tandem process. Other work has been published on nitrenes, carbenes and atomic O from photolysis of sulfilimines, sulfoxides, pyridine N-oxide and related compounds (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25), but by nature are one-step processes. Relatedly, simultaneous formation of reactive intermediates has also been reported.…”

Study and Applications of Tetrasubstituted Hypervalent Selenium–Halogen Species in Catalytic Electrophilic Halogenations

“…11 Dissociation of the strongly coordinating succinimide anion from the Br of NBS via protonation would also improve the availability of Br for electrophilic halogenation. In addition, it is known that a mild oxidizing agent is sufficient to oxidize Se(II) to Se(IV), 12 and the relatively low oxidation potential of Se(II)/Se(IV) 13 would be beneficial to the catalyst turnover.…”

“…Dissociation of the strongly coordinating succinimide anion from the Br of NBS via protonation would also improve the availability of Br for electrophilic halogenation. In addition, it is known that a mild oxidizing agent is sufficient to oxidize Se­(II) to Se­(IV), and the relatively low oxidation potential of Se­(II)/Se­(IV) would be beneficial to the catalyst turnover. Herein, we describe the study and applications of arylselenium-bearing ortho-substituted carboxylic acid or amide as catalysts in various electrophilic halogenation reactions.…”