Carboxylation of Aryl Triflates with CO<sub>2</sub> Merging Palladium and Visible-Light-Photoredox Catalysts
作者:Samir Kumar Bhunia、Pritha Das、Shantanu Nandi、Ranjan Jana
DOI:10.1021/acs.orglett.9b01532
日期:2019.6.21
visible-light-promoted, highly practical carboxylation of readily accessible aryl triflates at ambient temperature and a balloon pressure of CO2 by the combined use of palladium and photoredox Ir(III) catalysts. Strikingly, the stoichiometric metallic reductant is replaced by a nonmetallic amine reductant providing an environmentally benign carboxylation process. In addition, one-potsynthesis of a carboxylic
Radical Trifluoromethoxylation of Arenes Triggered by a Visible‐Light‐Mediated N−O Bond Redox Fragmentation
作者:Benson J. Jelier、Pascal F. Tripet、Ewa Pietrasiak、Ivan Franzoni、Gunnar Jeschke、Antonio Togni
DOI:10.1002/anie.201806296
日期:2018.10.15
method enables non‐directed functionalization of C−H bonds on a range of substrates, providing access to aryl trifluoromethyl ethers. This light‐driven process is distinctly different from conventional procedures and occurs through an OCF3 radical mechanism mediated by a photoredox catalyst, which triggers an N−O bond fragmentation. The pyridinium‐based trifluoromethoxylation reagent is bench‐stable and
zinc bromides and regioconvergent Negishi coupling with aryl or alkenyl triflates. The use of a suitable phosphine ligand favoring Pd migration enabled the selective formation of the linear cross‐coupling product. Subsequently, mixtures of secondary alkyl bromides were prepared from linear alkanes by standard bromination, and regioconvergent cross‐coupling then provided access to the corresponding linear
The present invention provides an activator in arylamination using a palladium compound as a catalyst, which is superior to conventional phosphines in stability and performance. With the phosphine sulfide as an activator, an arylamination reaction achieves improved selectivity to produce a desired aromatic amine in an obviously increased yield as compared with a reaction using the corresponding phosphine compound. Moreover, the phosphine sulfide of the invention is impervious to oxidation and exists stably in air and therefore sufficiently withstands use on an industrial scale.