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

摘要

The photolysis of triethylamine ( 1a ) in the presence of carbon dioxide leads to the hydrogenation of CO_(2), the α-C–C coupling of 1a , and the CO_(2) insertion into the α-C–H σ-bond of amine 1a . This reaction is proposed to proceed through the radical ion pair [R_(3)N~(?+)·CO_(2)~(?–)] generated by the photoionization of amine 1a and the electron capture by CO_(2). 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 ).