Photocatalytic Reductive Desulfonation of Aryl Tosylates

TL;DR

This paper introduces a new method to convert aryl tosylates into phenols using light, with high efficiency and without damaging other parts of the molecule.

Contribution

A visible-light photocatalytic method for reductive desulfonation of aryl tosylates is presented.

Findings

The method achieves up to 93% yield in converting aryl tosylates to phenols.

The process selectively cleaves the S–O bond without affecting other functional groups.

It offers an orthogonal deprotection strategy for use in organic synthesis and medicinal chemistry.

Abstract

This communication describes the reductive deprotection
of aryl
tosylates to their corresponding phenols in up to 93% yield using
visible-light photocatalysis. In this new methodology, the photoexcited
enolate generated from the deprotonation of 10-bromoanthracen-9-one
and subsequent excitation is capable of selectively cleaving the S–O
bond on the aryl tosylate substrate, releasing the phenolate anion.
Moreover, this deprotection method does not perturb common functional
groups. Thus, this transformation affords an orthogonal deprotection
strategy and has potential for use in the late-stage deprotection
of aryl tosylates in organic synthesis and medicinal chemistry. The
design, scope, and limitations are discussed.

Figures