A series of carbene complexes [PdBr2(iPr2-bimy)L] (C2âC13) with different types of co-ligands (L) have been tested for their catalytic activities in the carbonylative annulation of 2-iodophenol with phenylacetylene in DMF to afford the respective flavone 2a. Complex C12 with an N-phenylimidazole co-ligand showed the best activity and also afforded high yields when the substrate scope was extended to other aryl or pyridyl acetylenes. In addition, catalyst C12 was also efficient in the carbonylative annulation of 2-iodoaniline with acid chlorides giving the desirable 2-substituted 4H-3,1-benzoxazin-4-ones (4) in good yields. Additionally, this PdâNHC complex also proved to be a very efficient catalyst for the hydroxycarbonylation of iodobenzene derivatives at low catalyst loading and under low CO pressure. These results demonstrate the versatility and efficiency of this phosphine-free Pd(II)âNHC complex in different types of carbonylations of aryl iodides under mild conditions.
一系列含有不同类型
配体(L)的卡宾配合物[PdBr2(iPr2-bimy)L](C2至C13)被测试其在二甲基甲酰胺(
DMF)中催化
2-碘苯酚与
苯乙炔进行羰基化环化反应的活性,以制备相应的
黄酮2a。含有N-苯基
咪唑配体的配合物C12显示出最佳活性,并且在将底物范围扩展到其他芳基或
吡啶乙炔时也能获得高产率。此外,催化剂C12在催化
2-碘苯胺与酰
氯进行羰基化环化反应中也表现高效,以良好产率得到了理想的2-取代的4H-3,1-苯并噁嗪-4-酮(4)。此外,这种Pd-NHC配合物在对
碘苯衍
生物进行羟基羰基化反应中也证明是一种非常高效的催化剂,催化剂用量低且在低CO压力下。这些结果展示了这种不含膦的Pd(II)-NHC配合物在温和条件下对芳基
碘化物进行不同类型羰基化反应的多功能性和高效性。