An Electron-Deficient Diene as Ligand for Palladium-Catalyzed Cross-Coupling Reactions: An Efficient Alkylation of Aryl Iodides by Primary and Secondary Alkylzinc Reagents
作者:Qiang Liu、Hui Duan、Xiancai Luo、Yang Tang、Gang Li、Rong Huang、Aiwen Lei
DOI:10.1002/adsc.200800118
日期:2008.6.9
An electron-deficient diene, L1, was found to be an effective ligand in facilitating palladium-catalyzed Negishi couplings involving primary and secondary alkylzinc reagents. The reactions took place readily at 60 °C in THF with 5 mol% of a catalyst generated in situ from bis(acetonitrile)palladium dichloride [PdCl2(MeCN)2] and L1, and functional groups such as chloro, bromo, etc. attached to phenyl
发现缺电子的二烯L 1是促进钯催化的涉及伯烷基锌试剂和仲烷基锌试剂的Negishi偶联的有效配体。反应在60°C的THF中与5 mol%的由双(乙腈)二氯化钯[PdCl 2(MeCN)2 ]和L 1原位生成的催化剂轻松进行,并且对与苯环相连的氯,溴等官能团以及与反应位点相邻的β-H原子具有良好的耐受性。当单独使用异丙基氯化锌作为亲核试剂时,在我们的系统中也观察到了文献报道的反应中涉及的仲烷基锌试剂中存在问题的异构化。然而,当在L 1存在下使用i- Pr 2 Zn时,异构化被显着抑制。