Pd/Al<sub>2</sub>O<sub>3</sub>-catalysed redox isomerisation of allyl alcohol: application in aldol condensation and oxidative heterocyclization reactions
作者:Dániel Zsolnai、Péter Mayer、Kornél Szőri、Gábor London
DOI:10.1039/c5cy01722j
日期:——
The application of the Pd/Al2O3 catalyst in allylalcohol isomerization and subsequent aldol condensation and heterocyclization reactions is described. The activity of Pd/Al2O3 in these transformations is suggested to be due to the participation of the Lewis acidic sites of the support in the activation of the alcohol towards oxidative dehydrogenation by the metal and subsequent hydride transfer. The
描述了Pd / Al 2 O 3催化剂在烯丙醇异构化以及随后的醛醇缩合和杂环化反应中的应用。Pd / Al 2 O 3的活性这些转化的推测是由于载体的路易斯酸性位点参与了醇向金属的氧化脱氢和随后的氢化物转移的活化。所得的烯醇(酸酯)/醛可能会因载体的酸碱性质而进一步发生反应。在异构化产物的醛醇缩合反应中,贫电子的芳族醛和杂芳族醛显示出最高的活性,而带有给电子取代基的芳族醛在转化为相应的N-甲苯磺酰基亚胺后反应。1,2-二取代的芳族化合物在一锅多步反应序列中得到杂环产物。
Palladium-Catalyzed Hydrocarbonylative Cyclization Enabled by Formal Insertion of Aromatic C═N Bonds into Pd–Acyl Bonds
new formal insertion strategy via combination of reductive elimination and oxidative addition sequence was reported, in which the transient N-acyliminium ions formed via hydrocarbonylation function as key intermediates. This strategy has enabled a novel palladium-catalyzed hydrocarbonylative cyclization of azaarene-tethered alkenes or dienes via sequential insertion of a C═C bond, CO, and a C═N bond into