Base directed palladium catalysed Heck arylation of acrolein diethyl acetal in water
作者:Walid Al-Maksoud、Stéphane Menuel、Mohamad Jahjah、Eric Monflier、Catherine Pinel、Laurent Djakovitch
DOI:10.1016/j.apcata.2013.10.004
日期:2014.1
The selective Heck arylation of acrolein diethyl acetal catalysed by [Pd(NH3)4]Cl2 in the presence of RAME-β-CD in water as solvent is described. Depending on the base (i.e. NaOAc or HN(i-Pr)2) good to high selectivity's towards, respectively, the cinnamaldehydes 2 or the 3-arylpropionic esters 1 were achieved. The results support that depending on the base different palladium intermediate complexes
描述了在存在RAME-β-CD的水中作为溶剂的[Pd(NH 3)4 ] Cl 2催化的丙烯醛乙缩醛的选择性Heck芳基化。取决于对肉桂醛2或3-芳基丙酸酯1分别具有良好至高选择性的碱(即NaOAc或HN(i- Pr)2)。结果支持了根据碱形成了不同的钯中间体配合物。使用NaOAc,优先生成[ArPdX(H 2 O)2 ]}复合物,得到肉桂醛2。另一方面,在HN(i -Pr)存在下如图2所示,将产生L型配体[ArPdX(HN(i -Pr )2(H 2 O)]或[ArPdX(HN(i -Pr )2(HN(i -Pr)2))],从而导致在形成3-芳基丙酸酯的1。在过去,协调胺参与很可能是通过分子内形成酯的顺式β-H的消除。