Photoredox-Catalyzed Markovnikov Hydroamination of Alkenes with Azoles.

A visible-light induced intermolecular hydroamination of alkenes with azoles is reported, delivering pharmaceutically valuable N-benzyl azoles in high yields with excellent Markovnikov selectivity. Mechanistic studies suggest that the process is initiated by the energy transfer of the excited photocatalyst with alkenes, followed by the single electron reduction, protonation, and subsequent single electron oxidation to afford the key alkyl carbocation intermediate. This protocol exhibits advantages of broad functional group tolerance, excellent atom economy, high efficiency, and mild reaction conditions.

Redox-Neutral Cyclization of 2-Isocyanobiaryls through Photoredox/PPh Dual Catalysis.

The photoredox/PPh-mediated cyclization of 2-isocyanobiaryls has been developed. A substantial range of functional-group-rich phenanthridine derivatives were synthesized at room temperature in a highly selective and atom-economic manner. Mechanistic studies suggested that the cyclization process is probably mediated both by PhP radical cation with key 1,2-hydride transfer and hydrogen atom generated through O-H bond homolytic cleavage of PhP-OH radical intermediate.