Tailored Pyridine Enables Diverse Electrochemical Benzylic C–H Functionalization

Abstract

ABSTRACT C─H diversification strategies that enable access to various C─X (X = heteroatom) and C─C bonds are of central importance in synthetic chemistry. Here we present a benzylic C─H diversification protocol that merges electrochemical C─H pyridination with subsequent aminolysis or substitution to access unprotected benzylamines and a wide range of benzylic products. The electrochemical transformation proceeds in an undivided flow cell under oxidant‐ and transition‐metal‐free conditions and shows broad generality across electron‐rich, electron‐deficient, and halogenated alkylarenes. A key element is the use of a tailored pyridine with appropriate electronic properties, which suppresses undesired aromatic substitution while facilitating aminolysis and nucleophilic substitution of the pyridinium intermediate. The practicality of this method is underscored by a continuous operation in parallel microreactors, which furnished more than 100 g of benzylamine product.