Catalyst-Free Electrochemical Sulfonylation of Organoboronic Acids

Abstract

A simple and efficient electrochemical sulfonylation of organoboronic acids with sodium arylsulfinate salts has been reported for the first time. A variety of aryl, heteroaryl, and alkenylsulfones were obtained in good to excellent yields via a simple electrochemical sulfonylation of various arylboronic acids, heterocyclic boronic acids, or alkenylboronic acids with sodium arylsulfinate at room temperature in 5 h under the catalyst-free and additive-free conditions. A plausible mechanism has been proposed based on various radical-trapping and CV control experiments.

Challenges and opportunities on sustainable electrochemical transformations: application towards the synthesis of pharmaceuticals and precursors of drug-like molecules

“…Very recently, Ma and co-workers reported an interesting electrochemical sulfonylation of organoboronic acids to functionalised sulfones under metal-free conditions (Scheme 26). 101 Bench-stable sodium arylsulfinate salts 194 were used for this transformation, and overcome the associated limitations of conventional sulfonylating agents, such as sulfonyl halides and sulphur dioxide. This metal- and oxidative-free protocol enabled the synthesis of biologically active sulfone dapsone 197 , which is widely used as antibacterial drug in combination with rifampicin and clofazimine for the treatment of leprosy.…”

Electrochemical synthesis and transformation of organoboron compounds

“…Very recently, the electrochemical sulfonylation of organoboronic acids with sodium arylsulfinate salts has been reported by Ma and co-workers (Scheme 22e). 58 A variety of aryl–aryl and aryl–alkenyl sulfones were prepared in high yields with high functional group tolerance at room temperature.…”

Remote Radical 1,3-, 1,4-, 1,5-, 1,6- and 1,7-Difunctionalization Reactions

“…In addition to traditional homolytic bond cleavage-based radical reactions induced by radical initiators or photolysis [ 15 , 16 , 17 ], other methods such as single electron transfer reagents [ 18 , 19 , 20 , 21 , 22 ], catalytic photoredox [ 23 , 24 , 25 , 26 , 27 , 28 ], and electrochemical reactions [ 29 , 30 , 31 , 32 , 33 , 34 , 35 ] have been developed and are gaining increasing popularity. For the remote 1,3-, 1,4-, 1,5-, 1,6- and 1,7-difunctionalization reactions presented in this paper, the initial addition of the radical X is followed by radical rearrangement through resonance, hydrogen atom transfer (HAT), group transfer, or opening of strained-rings to relocate the position of the radical.…”