Oxidation of Trialkylamines by BrCCl3: Scope, Applications and Mechanistic Aspects

The catalyst-free photochemical reaction of trialkylamines and BrCCl3 induced by visible light was investigated. The outcome of the reaction was found to depend strongly on the nature of the amine substrates. N-Methyl-1,2,3,4-tetrahydroisoquinolines give 3,4-dihydroisoquinolinium salts, whereas aliphatic trialkylamines produce hydrohalide salts and streptocyanines as the major products. The addition of KCN inhibits streptocyanine formation, and results in the clean formation of -aminonitriles instead. The light-absorbing species and the underlying reaction mechanism were studied by DFT calculations and experimental observations.