56704-84-8Relevant articles and documents
Calixarene-derived mono-iminophosphoranes: Highly efficient ligands for palladium- and nickel-catalysed cross-coupling
Monnereau, Laure,Semeril, David,Matt, Dominique
, p. 1351 - 1360 (2013)
The first mono-iminophosphoranes based on a calix[4]arene skeleton have been synthesised and tested in the arylation of aryl bromides and aryl chlorides. Combining these ligands with [Pd(OAc)2] or [Ni(cod) 2] resulted in highly active Suzuki-Miyaura and Kumada-Tamao-Corriu cross-coupling catalysts, respectively. TOFs up to ca. 4×105 mol(ArBr)×mol(M)-1×h-1 were obtained in each case. The remarkable activities observed probably arise from the ligands' ability to form complexes with cavity-entrapped "MArX" moieties (endo-complexes), their highly crowded metal environment favouring formation of mono-ligated intermediates over that of less reactive bis-ligated ones. Possible supramolecular interactions within the cavity involving the receptor wall and the aromatic substrate may also significantly influence the reaction rates, notably by increasing the proportion of endo-complexes. Copyright
