Facile Buchwald-Hartwig coupling of sterically encumbered substrates effected by PNP ligands

摘要

The diphosphinoamine ligands [(Ph2P)(2)N(Ar); 1 (Ar = C6H5), 2 (Ar = 2,6-iPr(2)C(6)H(3))] were effectively utilized in Buchwald-Hartwig coupling of a range of sterically demanding substrates. The reaction was carried out using conventional and microwave routes and the latter reduces the reaction time from 3 d to 15-30 min. A broad substrate scope was achieved in this protocol and most of the coupling products are isolated on a mutligram scale. DFT calculations were carried out to elucidate the reaction mechanism.