Copper Mediated Chemo‐ and Stereoselective Cyanation Reactions

Light-Triggered, Ni-Catalyzed Cyanation of Aryl Triflates with 1,4-Dicyanobenzene as the CN Source

A light-triggered, Ni-catalyzed cyanation of aryl triflates was herein reported, which provides a benign photochemical synthesis of aryl nitriles using 1,4-dicyanobenzene as the CN source instead of HCN or a metallic CN source. This mild method uses a readily available bisphosphine ligand and a soluble organosilicon reagent as the reductant and is carried out under purple light without an external photocatalyst. This cyanation was effective for aryl triflates derived from phenols and bisphenols as well as lignin-derived phenolic compounds, demonstrating its potential utility for the synthesis of aryl nitriles from biomass.

Photo and copper dual catalysis for allene syntheses from propargylic derivatives via one-electron process

Different from the traditional two-electron oxidative addition-transmetalation-reductive elimination coupling strategy, visible light has been successfully integrated into transition metal-catalyzed coupling reaction of propargylic alcohol derivatives highly selectively forming allenenitriles: specifically speaking, visible light-mediated Cu-catalyzed cyanation of propargylic oxalates has been realized for the general, efficient, and exclusive syntheses of di-, tri, and tetra-substituted allenenitriles bearing various synthetically versatile functional groups. A set of mechanistic studies, including fluorescence quenching experiments, cyclic voltammetric measurements, radical trapping experiments, control experiments with different photocatalyst, and DFT calculation studies have proven that the current reaction proceeds via visible light-induced redox-neutral reductive quenching radical mechanism, which is a completely different approach as compared to the traditional transition metal-catalyzed two-electron oxidative addition processes.

Preparation of nitriles from aldehydes using ammonium persulfate by means of a nitroxide-catalysed oxidative functionalisation reaction

A methodology for the preparation of nitriles from aldehydes by means of an oxidative functionalisation reaction is reported. It employs ammonium persulfate as both the primary oxidant and the nitrogen source, and a catalytic amount of a nitroxide. It is applicable to a range of structurally diverse (hetero)aromatic aldehydes furnishing the nitrile products in 30-97% isolated yield. Given the ready accessibility of aldehydes and that ammonium persulfate is cheap and less toxic than many other reagents for generating nitriles, this methodology offers a simple and easy to use approach to this valuable class of compounds.