Triaryl phosphine-functionalized N-heterocyclic carbene ligands for Heck reaction
Ai-E Wang, Jian-Hua Xie, Li-Xin Wang and Qi-Lin Zhou*
*State Key Laboratory, Institute of Elemento-organic Chemistry, Nankai
University, Tianjin 300071, China, Email: qlzhou
nankai.edu.cn
A.-E. Wang, J.-H. Xie, L.-X. Wang, Q.-L. Zhou, Tetrahedron, 2005, 61, 259-266.
DOI: 10.1016/j.tet.2004.10.049
Abstract
Palladium complexes of triaryl phosphine-functionalized imidazolium salts were successfully applied in the palladium-catalyzed Heck reaction. A highly efficient system is described for the coupling of a wide array of aryl bromides and iodides with acrylates and styrene derivatives in excellent yield.
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Details
The document discusses the development of triaryl phosphine-functionalized N-heterocyclic carbene (NHC) ligands for the palladium-catalyzed Heck reaction. These ligands were synthesized and their palladium complexes, generated in situ, were tested for their efficiency in the Heck reaction. The study found that using 1 mol% of Pd(dba)2 and 1 mol% of the ligand 6c in the presence of 2 equivalents of K2CO3 in DMAc was highly effective for coupling a wide range of aryl bromides and iodides with acrylates, yielding excellent results. The coupling of 4-bromotoluene with various styrene derivatives also showed good outcomes. The research highlighted the stability and reactivity of NHC ligands compared to traditional phosphine ligands, which are sensitive to air and moisture. The introduction of bulky groups to the N-phenyl ring of the NHC ligands was found to enhance the catalyst's activity. The study concluded that these new ligands are efficient for Heck reactions, providing high yields and stability under reaction conditions. The research was supported by various Chinese scientific foundations and conducted at Nankai University.
Key Words
ID: J72-Y2005-2780
