Ferrocenyl iminophosphine ligands in Pd-catalysed Suzuki couplings

Abstract

A mixture of Pd2(dba)3/{η-C5H 4CHN[CH(CH3)(Nap)]}Fe[η-C5H 4P(tBu)2] efficiently catalyzes the Suzuki reactions of a variety of bulky aryl halides and aryl- and alkyl-boronic acids, affording the desired cross-coupling biaryl products in quantitative isolated yields under mild conditions and at low (1 × 10-6-1 mol%) Pd loadings. Spectroscopic (NMR & ESI) analysis of the mixture of Pd 2(dba)3, the hybrid [P,N] ligands, and aryl halides revealed different structural forms of oxidative addition products that are dependent on the substituent on the imino nitrogen. © 2011 Elsevier B.V. All rights reserved.