2-Phosphinoimidazole Ligands: N–H NHC or P–N Coordination Complexes in Palladium-Catalyzed Suzuki–Miyaura Reactions of Aryl Chlorides
2-Phosphinoimidazole Ligands: N–H NHC or P–N Coordination Complexes in Palladium-Catalyzed Suzuki–Miyaura Reactions of Aryl Chlorides
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DOI：
10.1021/acs.organomet.1c00165
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发表时间：
2021-06
期刊：
影响因子：
2.8
通讯作者：
Erin E. Martinez;Alexandra J. S. Larson;Sydney K. Fuller;Kathryn M. Petersen;Stacey J. Smith;D. Michaelis
中科院分区：
文献类型：
--
作者：
Erin E. Martinez;Alexandra J. S. Larson;Sydney K. Fuller;Kathryn M. Petersen;Stacey J. Smith;D. Michaelis
我们报道了两个钯2-（二烷基膦基）咪唑配合物的合成，并证明其作为Suzuki-Miyaura反应的催化剂在室温下与（杂）芳基氯的活性。我们的机理研究表明，这些钯配合物之间存在的P-N配位和N-H NHC形式的配体的平衡混合物。我们的研究表明，N-H NHC形式可能是重要的Suzuki-Miyaura反应与芳基氯的高催化活性。这些反应在室温或接近室温下以良好至优异的产率进行。杂芳基氯在较低的催化剂负载下也是反应性的。
We report the synthesis of two palladium 2-(dialkylphosphino)imidazole complexes and demonstrate their activity as catalysts for Suzuki–Miyaura reactions with (hetero)aryl chlorides at room temperature. Our mechanistic studies demonstrate that these palladium complexes exist as an equilibrium mixture between the P–N coordinated and N–H NHC forms of ligand. Our studies suggest that the N–H NHC form may be important for high catalytic activity in Suzuki–Miyaura reactions with aryl chlorides. These reactions proceed at or near room temperature in good to excellent yields. Heteroaryl chlorides are also reactive at lower catalyst loadings.