RESUMO
A methodology for the synthesis of (hetero)aromatic nitriles from aryl chlorides at room temperature has been developed. This methodology uses an air and moisture stable nickel(ii) XantPhos precatalyst and Zn(CN)2 as the cyanide (CN-) source.
RESUMO
The palladium-catalyzed cyanation of Ar-X (X = I, Br, Cl, OTf, and H) allows for an efficient access towards benzonitriles. After its discovery in 1973 and following significant improvements in recent decades, this methodology has become nowadays the most popular for preparation of substituted aromatic nitriles. In this critical review, we summarize the important developments in this area from 2000 until 2010 (151 references).
Assuntos
Técnicas de Química Sintética/métodos , Cianetos/química , Nitrilas/síntese química , Paládio/química , Catálise , Nitrilas/químicaRESUMO
A general protocol for the cyanation of aryl halides with the nontoxic cyanide source K4[Fe(CN)6] using copper catalysis and a ligand system based on 1-alkylimidazoles is presented. The advantages of this system are the high selectivity, a unique substrate range, easy handling, and inexpensive reagents.
Assuntos
Brometos/química , Cobre/química , Cianetos/química , Bromobenzenos/química , Catálise , Estrutura MolecularRESUMO
A new advantageous cyanating agent, potassium hexacyanoferrate(II), is described for the palladium-catalyzed cyanation of aryl halides. All cyanide ions on the iron(II) center can be transferred to the aryl halide using palladium(II) acetate and dppf as the catalyst. Under optimized reaction conditions good yields of benzonitriles and unprecedented catalyst productivities are observed.
