A bis(oxazolinyl)pyrrole as a new monoanionic tridentate supporting ligand: Synthesis of a highly active palladium catalyst for Suzuki-type C-C coupling

Reaction of pyrrole-2,5-biscarbonitrile with 2-amino-2-methyl-1-propanol gave the bis{2-(4,4'-dimethyl-4,5-dihydrooxazolyl)}pyrrole (dmoxpH) (1), which was deprotonated and reacted with [PdCl2(COD] to give [Pd-2(dmoxp)(2)Cl-2] (2) and [Pd-3(dmoxp)(2)Cl-4] (3). The former is an active catalyst in the Suzuki cross coupling of phenylboronic acid with activated and nonactivated aryl bromides at 70 degreesC and catalyst / substrate ratios of 10(-4) to 10(-5).