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
[Pd2(dmoxp)2Cl2] (2) and [Pd3(dmoxp)2Cl4] (3). The
former is an active catalyst in the Suzuki cross coupling
of phenylboronic acid with activated and nonactivated
aryl bromides at 70 °C and catalyst/substrate ratios of
10-4 to 10-5.