One-pot H/D exchange and low-coordinated iron electrocatalyzed deuteration of nitriles in D2O to α,β-deuterio aryl ethylamines

Abstract Developing a step-economical approach for efficient synthesis of α , β -deuterio aryl ethylamines ( α , β -DAEAs) with high deuterium ratios using an easy-to-handle deuterated source under ambient conditions is highly desirable. Here we report a room-temperature one-pot two-step transformation of aryl acetonitriles to α , β -DAEAs with up to 92% isolated yield and 99% α , β -deuterium ratios using D 2 O as a deuterium source. The process involves a fast α -C − H/C − D exchange and tandem electroreductive deuteration of C ≡ N over an in situ formed low-coordinated Fe nanoparticle cathode. The moderate adsorptions of nitriles/imine intermediates and the promoted formation of active hydrogen (H*) on unsaturated Fe sites facilitate the electroreduction process. In situ Raman confirms co-adsorption of aryl rings and the C ≡ N group on the Fe surface. A proposed H*-addition pathway is confirmed by the detected hydrogen and carbon radicals. Wide substrate scope, parallel synthesis of multiple α , β -DAEAs, and successful preparation of α , β -deuterated Melatonin and Komavine highlight the potential.