Photolysis of Tertiary Amines in the Presence of CO₂: The Paths to Formic Acid, α-Amino Acids, and 1,2-Diamines

Abstract

The photolysis of triethylamine (1a) in the presence of carbon dioxide leads to the hydrogenation of CO, the α-C-C coupling of 1a, and the CO insertion into the α-C-H σ-bond of amine 1a. This reaction is proposed to proceed through the radical ion pair [RN·CO] generated by the photoionization of amine 1a and the electron capture by CO. The presence of lithium tetrafluoroborate in the reaction medium promotes the efficient and stereoselective α-C-C coupling of 1a by enhancing the production of α-dialkylamino radicals and the isomerization of N,N,N',N'-tetraethylbutane-2,3-diamine (4a).