Pd(OAc)۲/۱,۱′-Methylene-۳,۳′-bis[(N-(isopropyl)imidazol-۲-ylidene]: An Efficient Catalyst for the Heck Arylation of Various Olefins

The Mizoroki-Heck coupling reaction has been carried out using Pd(OAc)۲ and bisimidazolium (۱,۱′-methylene-۳,۳′-bis[(N-(isopropyl)imidazol-۲-ylidene]dibromide) for aryl bromides as well as less reactive chlorobenzene with mono- and di-substituted olefins. Only ۰.۰۲۵ mol% of Pd(II) shows a high activity toward the coupling reaction with turnover number (TON) ≈ ۶۰۰-۳۹۶۰. Further, this catalyst system, Pd(OAc)۲/Bisimidazolium, exhibits the excellent selectivity for the trans-isomer coupling products and the terminal arylation coupling products for mono- and di-substituted olefins, respectively. The nature of olefins (n-butyl acrylate, styrene, and ۱,۱-disubstituted olefins) has a significant contribution on the yield of the coupling products.