Palladium-Catalyzed Allylation of Pronucleophiles with Alkynes at 50 °C – Remarkable Effect of 2-(Dicyclohexylphosphanyl)-2′-(dimethylamino)biphenyl as Ligand
Monoallylation and monoalkylation of diketones and β-keto esters with allylic and benzylic alcohols catalysed by [Cp*Co(CH3CN)3][SbF6]2 (I) are reported. The method does not require any additive and affords regioselective products. The mechanistic investigations were done by in situ 1H NMR spectroscopy as well as control experiments. It has been shown that reactions proceed via η3-allyl complex formation or
报道了[Cp*Co(CH 3 CN) 3 ][SbF 6 ] 2 ( I )催化的二酮和β-酮酯与烯丙醇和苄醇的单烯丙基化和单烷基化。该方法不需要任何添加剂并提供区域选择性产物。通过原位1 H NMR 光谱以及对照实验进行了机理研究。已表明反应通过形成 η 3 -烯丙基络合物或烯丙基醚中间体进行。烷基化仅通过醚中间体发生。所得烯丙基化和烷基化产物已用于合成十一种新的三取代吡唑和一种吡唑啉酮。
Formation of a Quaternary Carbon Center through the Pd(0)/PhCOOH-Catalyzed Allylation of Cyclic β-Keto Esters and 1,3-Diketones with Alkynes
作者:Nitin T. Patil、Yoshinori Yamamoto
DOI:10.1021/jo0490144
日期:2004.9.1
Formation of a quaternarycarboncenter through the allylation of β-ketoesters and 1,3-diketones with alkynes is accomplished by the use of Pd(0)/benzoic acid catalyst. Reactions of various cyclic β-ketoesters and 1,3-diketones with alkynes in the presence of Pd2dba3·CHCl3 (5 mol %), PPh3 (40 mol %), and PhCOOH (10 mol %) proceeded at 100 °C in toluene (5 M) to give the corresponding allylation products
Without prior activation of allyl alcohols, allylation of a variety of active methylene compounds with allyl alcohols proceeds smoothly at rt-50degreesC in the presence of catalytic amounts of Pd(OAc)(2) (1-10mol%), Et3B (30-240 mol%), a phosphine ligand (1-20 mol%), and a base (0 to 50-60 mol%). (C) 2003 Elsevier Ltd. All rights reserved.