Dicyclohexylphosphino cyrhetrene: Synthesis, characterization and catalytic evaluation toward Suzuki-Miyaura cross-coupling reaction of aryl bromides and chlorides

Reaction of cyrhetrene ((eta(5)-C5H5)Re(CO)(3)) with n-butyllithium (1.0 equiv, -78 degrees C) and then CIPCy2 (Cy = cyclohexyl) gives the new cyrhetrenyl-phosphino ligand (eta(5)-C5H4PCy2)Re(CO)(3) which was isolated as a pure sample in 86% yield and characterized by standard spectroscopic techniques (FT-IR, H-1, C-13 and P-31 NMR), MS, X-ray diffraction and Elemental Analysis). This rhenium containing cyrhetrenyl phosphine combined with Pd(OAc)(2) (2:1 mol ratio) resulted an efficient catalytic system for Suzuki couplings of aryl bromides and aryl chlorides with phenylboronic acid. The catalyst exhibits a high activity, with conversions of 100% after 20 min. (C) 2017 Elsevier B.V. All rights reserved.