Synthesis of Calixarene-Based Bis(iminophosphoranes) and Their Use in Suzuki-Miyaura Cross-Coupling
作者:Laure Monnereau、David Sémeril、Dominique Matt
DOI:10.1002/ejoc.201200082
日期:2012.5
Calix[4]arene-derived bis(iminophosphoranes) have been synthesised and assessed in palladium-catalysed cross-couplings between phenylboronic acid and aryl bromides orchlorides. TOFs of up to 35100 mol(ArPh formed) mol(Pd)–1 h–1were observed in the reaction with 4-bromoanisole. The ligands showed higher activities than the parent calixarene–diphosphanes. Their relatively good performances possibly arise
bis-(phosphine sulfide) (4) have been synthesized. A single crystal X-ray diffraction study was carried out for bis(phosphine oxide) 3, which revealed a pinched cone conformation for the calixarene core. In the solid state, each calixarene is linked to two other calixarenes via hydrogen bonds involving the phosphoryl groups as well as two of the four hydroxyl groups, thereby generating a supramolecular polymeric