Programmable Mono-/Di-alkylation of Amines with Aldehydes Over a Pdδ−–H Electrocatalyst

Abstract

Programmable amine N-alkylation provides a new method to combine the required alkyl groups with amine molecules according to actual demand and to precisely regulate the biological and pharmaceutical properties of life science amine molecules. However, only the electrochemical mono-methylation of amines has been achieved via C─N coupling with CO₂ accompanied by an unsatisfactory Faraday efficiency (FE) lower than 10%. Herein, we developed programmable electrocatalytic N-alkylation of amines with two controllable alkyl groups and one methyl group. Both experimental characterization and density functional theory (DFT) calculations have demonstrated the critical role of electron-enriched Pd metals in transforming amines into alkylamines with two chosen alkyl groups and a methyl group. Moreover, the electrocatalytic transformation of amines to alkylamines with satisfactory FE values (86%–96%) has been achieved, further expanding the scope of electrochemical C─N coupling and possibly opening a new world of electrochemical amine N-alkylation.