Department of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
Chemistry. 2010 Apr 6;16(13):4075-81. doi: 10.1002/chem.200903309.
Dichloro-bis(aminophosphine) complexes are stable depot forms of palladium nanoparticles and have proved to be excellent Suzuki-Miyaura catalysts. Simple modifications of the ligand (and/or the addition of water to the reaction mixture) have allowed their formation to be controlled. Dichlorobis[1-(dicyclohexylphosphanyl)piperidine]palladium (3), the most active catalyst of the investigated systems, is a highly convenient, reliable, and extremely active Suzuki catalyst with excellent functional group tolerance that enables the quantitative coupling of a wide variety of activated, nonactivated, and deactivated and/or sterically hindered functionalized and heterocyclic aryl and benzyl bromides with only a slight excess (1.1-1.2 equiv) of arylboronic acid at 80 degrees C in the presence of 0.2 mol % of the catalyst in technical grade toluene in flasks open to the air. Conversions of >95 % were generally achieved within only a few minutes. The reaction protocol presented herein is universally applicable. Side-products have only rarely been detected. The catalytic activities of the aminophosphine-based systems were found to be dramatically improved compared with their phosphine analogue as a result of significantly faster palladium nanoparticle formation. The decomposition products of the catalysts are dicyclohexylphosphinate, cyclohexylphosphonate, and phosphate, which can easily be separated from the coupling products, a great advantage when compared with non-water-soluble phosphine-based systems.
二氯双（氨基膦）配合物是钯纳米粒子的稳定储存形式，已被证明是出色的铃木-宫浦（Suzuki-Miyaura）催化剂。通过对配体进行简单的修饰（和/或向反应混合物中添加水），可以控制其形成。二氯双[1-（二环己基膦基）哌啶]钯（3）是所研究体系中最活跃的催化剂，它是一种非常方便、可靠且极其活跃的铃木催化剂，具有出色的官能团耐受性，可使各种活化、非活化、以及失活和/或空间位阻的官能化和杂环芳基和苄基溴化物与仅略过量（1.1-1.2 当量）的芳基硼酸在 80°C 下定量偶联，在空气中打开烧瓶的技术级甲苯中仅使用 0.2 mol %的催化剂即可。通常在短短几分钟内即可实现超过 95%的转化率。本文提出的反应方案具有普遍适用性。很少检测到副产物。由于钯纳米粒子的形成速度明显加快，基于氨基膦的体系的催化活性与它们的膦类似物相比有了显著提高。催化剂的分解产物为二环己基次膦酸酯、环己基膦酸酯和磷酸盐，与不溶于水的膦基体系相比，这些产物很容易与偶联产物分离，这是一个很大的优势。
