Microwave accelerated Suzuki coupling of chloro-aryl phosphine-oxides: A method for introducing diversity into phosphine ligands

There is a demand for methodology that can rapidly produce families of catalysts for catalyst–structure–performance studies. The results reported here show microwave accelerated Suzuki coupling of a range of boronic acids with chloro-aryl phosphine-oxides can give high yields of arylated phosphine oxides. Chloro-aryl phosphine-oxide substrates have been found to be unreactive in previous studies, but in these examples, the combination of a highly active (but short lived) catalyst and instantaneous microwave heating at 140 °C allows the reactions to proceed. These cross-coupling reactions are being used as the basis for a rapid synthesis of phosphine ligands (readily available by microwave-assisted reduction of the phosphine oxides).

Suzuki coupling of chloro-aryl phosphine-oxides does not take place under conventional heating conditions, but using a suitable catalyst and microwave heating allows cross-coupling to proceed in high yield. Combining these reactions with microwave heated PO reduction allows the preparation of aryl-substituted phosphine ligands.Figure optionsDownload as PowerPoint slide