Facile Oxidative Addition of Organic Halides to Heteroleptic and Homoleptic Pd⁰–N‐Heterocyclic Carbene Complexes

Abstract

Abstract Novel heteroleptic Pd 0 complexes with an N‐heterocyclic carbene (NHC) ligand [(Me 3 P)Pd(NHC)] (NHC = IPr, 1 ; SIPr, 2 ) were obtained from [Pd(CH 2 =CHPh)(PMe 3 ) 2 ] and an equivalent of NHC [NHC = 1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene (IPr) or 1,3‐bis(2,6‐diisopropylphenyl)‐4,5‐dihydroimidazol‐2‐ylidene (SIPr)]. Further treatments of complexes 1 and 2 with an additional equimolar NHCafforded the corresponding bis(NHC)–Pd 0 complexes [Pd(NHC) 2 ] (NHC = IPr, 3 ; SIPr, 4 ). Complexes 1 – 4 readily reacted with dichloromethane or chloroform to give C–Cl oxidative addition products. In addition, the reactivity of complex 2 toward other organic halides such as bromobenzene, trans ‐1,2‐dichloroethylene, and 5,5′‐dibromo‐2,2′‐bithiophene to produce the corresponding oxidative addition products was investigated. Finally, the ligand replacement of complex 1 with a chelating phosphane was examined.