Photo-oxidation and Thermal Oxidations of Triptycene Thiols by Aryl Chalcogen Oxides

Overview

Journal ACS Omega

Publisher American Chemical Society

Specialty Chemistry

Date 2020 Dec 30

PMID 33376871

Authors

Satyanarayana M Chintala

Peter F Maness

John T Petroff 2nd

John C Throgmorton

Miao Zhang

Sara M Omlid

Ryan D McCulla

Affiliations

Soon will be listed here.

Abstract

Oxidation of thiols yield sulfenic acids, which are very unstable intermediates. As sulfenic acids are reactive, they form disulfides in the presence of thiols. However, sulfenic acids also oxidize to sulfinic acids (-SOH) and sulfonic acids (-SOH) at higher concentrations of oxidants. Hydrogen peroxide is a commonly used oxidant for the oxidation of thiols to yield sulfenic acids. However, hydrogen peroxide also oxidizes other reactive functional groups present in a molecule. In this work, the reaction intermediates arising from the oxidation of sterically hindered thiols by aryl chalcogen oxides, dibenzothiophene -oxide (DBTO), dibenzoselenophene -oxide (DBSeO), and dibenzotellurophene -oxide (DBTeO), were investigated. Photodeoxygenation of DBTO produces triplet atomic oxygen [O(P)], which has previously shown to preferentially react with thiols over other functional groups. Similarly, aryl selenoxides have also shown that they can thermally react selectively with thiols at room temperature to yield disulfides. Conversely, aryl telluroxides have been reported to oxidize thiols to disulfides thermally with no selectivity toward thiols. The results from this study demonstrate that sulfenic acids are an intermediate in the oxidation of thiols by DBTeO and by photodeoxygenation of DBTO. The results also showed that the oxidation of thiols by DBSeO yields sulfonic acids. Triptycene-9-thiol and 9-fluorotriptycene-10-thiol were for the thiols used in this oxidation reaction. This work expands the list of oxidants that can be used to oxidize thiols to obtain sulfenic acids.

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