Palladacycles bearing pendant benzamidinate ligands as catalysts for the Suzuki and Heck coupling reactions

Abstract

Three pendant benzamidines [Ph-C(=NC6H5)-{NH(CH2)(2)NMe2}] (1), [Ph-C(=NC6H5)-{NH(CH2PY)}] (2) and [Ph-C (=NC6H5)-{NH(o-C6H4)(oxazoline)}] (3) are described. Reactions of 1, 2 or 3 with one molar equivalent of Pd(OAc)(2) in THF give the palladacyclic complexes [Ph-C{-NH(eta(1)-C6H4)} {=N(CH2)(2)NMe2}]Pd(OAc) (4), [Ph-C{NH(eta(1)-C6H4} {=N (CH2Py)}]Pd(OAc) (5) and [Ph-C{-NH(eta(1)-C6H4)} {=N(o-C6H4)(oxazoline)}]Pd(OAc) (6), respectively. Treatment of 4, 5 or 6 with excess of LiCl in chloroform affords [Ph-C{-NH(eta(1)-C6H4)} {=N(CH2)(2)NMe2}]PdCl (7), [Ph-C{-NH(eta(1)-C6H4} {=N(CH2Py}]PdCl (8) and [Ph-C{NH(eta(1)- C6H4)} {=N(o-C6H4)(oxazoline)}]PdCl (9). The crystal and molecular structures are reported for compounds 1, 3, 5, 6 and 7. The application of these palladacyclic complexes to the Suzuki and Heck coupling reactions was examined.(c) 2005 Elsevier Ltd. All rights reserved.