C-H activation has emerged as a powerful tool in synthesis of medicines, industrial materials and natural products and has the potential to revolutionize organic chemical industries.In this work, H/D exchange shows that C-H bonds adjacent to –OH or –NH2 groups can be electrochemically activated over catalytic electrodes.Though useful in their own right, these deuteration studies also uncovered a mild, electrocatalytic method for alkylating amines with alcohols. This reaction is essentially an electrochemical version of the borrowing hydrogen methodology. Methanol, primary, secondary, and bulkier alcohols such as cyclohexanol and benzyl alcohols all readily alkylate simple secondary amines such as pyrrolidine. Via alkylation of ammonia, lab staples triethylamine and N,N-diisopropylethylamine (Hunig’s base) are easily made from the corresponding alcohols. Many active chemicals, pharmaceuticals, herbicides, conducting polymers and components of organic diodes contain alkylamines. For many years, compounds in this class have been made via classical methods such as amide or nitrile reduction, reductive alkylation, and electrophilic alkylation. These conventional methods have been improved over the years, but they suffer from several disadvantages: (a) the use of alkyl halides or strong reducing agents which are less benign to the environment, (b) the generation of wasteful salt byproducts and (c) lack of selectivity which leads to the formation of quaternary ammonium ions. Electroactivated reductive alkylation of amines with alcohol and water as solvent provides a new and a more benign approach for the synthesis of alkylamines.

Electroactivated alkylation of amines with alcohols via borrowing hydrogen methodology

2019 Spring National Meeting

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