A highly efficient metal-free catalytic system for the aerobic photocyanation of tertiary amines with visible light is reported. The use of air as terminal oxidant offers an improved safety profile compared with pure oxygen, the used compact fluorescent lamp (CFL) light sources are highly economical, and no halogenated solvents are required. This system not only proves to be effective for a wide variety of trialkylamines, pharmaceuticals, and alkaloids but remarkably also allows the lowest catalyst loading (0.00001 mol% or 0.1 ppm) ever reported for an organic dye. Bruylants reactions and C-alkylation/decyanations were performed on the obtained α-aminonitriles to demonstrate the postfunctionalization of complex molecules. The catalytic system is furthermore applied in the short and effective syntheses of the alkaloids (±)-crispine A and the tetraponerines T7 and T8.

The Stevens rearrangement of nitrile-stabilized ammonium ylides in conjunction with the reductive removal of the nitrile function permits the facile construction of α-branched amines from α-aminonitriles. We employed this reaction sequence for the preparation of (±)-laudanosine, (±)-laudanidine and (±)-armepavine, (±)-7-methoxycryptopleurine, and (±)-xylopinine from two closely related and readily accessible bicyclic α-aminonitriles. The final products were obtained in high to almost quantitative yields (71-98%) from the quaternary ammonium salts obtained by N-alkylation of these starting materials.

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 α‐aminonitriles instead. The light‐absorbing species and the underlying reaction mechanism were studied by DFT calculations and experimental observations.

When the products of a Strecker reaction of 1,2,3,4-tetrahydroisoquinolines with aromatic aldehydes are quaternized with alkyl triflates and subsequently treated with base, a ring expansion to 6,7,8,13-tetrahydro-5H-dibenzo[c,f]azonine-5-carbonitriles takes place. The nine-membered cyclic products can be obtained in good yields (78-89%) in a process involving the [1,4]-sigmatropic rearrangement of a nitrile-stabilized ammonium ylide. The reaction sequence provides a new, simple, and efficient method for the synthesis of these unusual N-heterocycles.

Herein, the design and development of a new one-pot and metal-free oxidative C−H activation/aza-Prins type cyclization of alkynylamines is reported. The scope of this method was demonstrated by the preparation of ten new pyrido[2,1-a]isoquinolines in moderate to high yields (38−92%). Furthermore, a mechanistic proposal for the alkyne aza-Prins cyclization is described based on DFT calculations.