Generation of non-stabilized alkyl radicals from thianthrenium salts for C-B and C-C bond formation

Sulfonium salts bearing a positively charged sulfur atom with three organic substituents have intrigued chemists for more than a century for their unusual structures and high chemical reactivity. These compounds are known to undergo facile single-electron reduction to emerge as a valuable and alternative source of aryl radicals for organic synthesis. However, the generation of non-stabilized alkyl radicals from sulfonium salts has been a challenge for several decades. Here we report the treatment of S-(alkyl) thianthrenium salts to generate non-stabilized alkyl radicals as key intermediates granting the controlled and selective outcome of the ensuing reactions under mild photoredox conditions. The value of these reagents has been demonstrated through the efficient construction of alkylboronates and other transformations, including heteroarylation, alkylation, alkenylation, and alkynylation. The developed method is practical, and provides the opportunity to convert C-OH bond to C-B and C-C bonds. The generation of non-stabilized alkyl radicals from sulfonium salts has been a challenge for several decades. Here, the authors show the treatment of S-(alkyl) thianthrenium salts, which can generate non-stabilized alkyl radicals as key intermediates that enable controlled and selective reactions under mild photoredox conditions.

Automated summary

The authors present a method for generating non-stabilized alkyl radicals as key intermediates from S-(alkyl) thianthrenium salts, allowing for controlled and selective reactions under mild photoredox conditions. This approach has been shown to successfully construct alkylboronates and other important compounds, demonstrating its practicality and versatility in organic synthesis.