Littke Adam F, Fu Gregory C
Massachusetts Institute of Technology, Department of Chemistry, 77 Massachusetts Avenue, Room 18-411, Cambridge 02139-4307, USA.
Angew Chem Int Ed Engl. 2002 Nov 15;41(22):4176-211. doi: 10.1002/1521-3773(20021115)41:22<4176::AID-ANIE4176>3.0.CO;2-U.
Collectively, palladium-catalyzed coupling reactions represent some of the most powerful and versatile tools available to synthetic organic chemists. Their widespread popularity stems in part from the fact that they are generally tolerant to a large number of functional groups, which allows them to be employed in a wide range of applications. However, for many years a major limitation of palladium-catalyzed coupling processes has been the poor reactivity of aryl chlorides, which from the standpoints of cost and availability are more attractive substrates than the corresponding bromides, iodides, and triflates. Traditional palladium/triarylphosphane catalysts are only effective for the coupling of certain activated aryl chlorides (for example, heteroaryl chlorides and substrates that bear electron-withdrawing groups), but not for aryl chlorides in general. Since 1998, major advances have been described by a number of research groups addressing this challenge; catalysts based on bulky, electron-rich phosphanes and carbenes have proved to be particularly mild and versatile. This review summarizes both the seminal early work and the exciting recent developments in the area of palladium-catalyzed couplings of aryl chlorides.
钯催化偶联反应总体上是合成有机化学家可用的一些最强大、最通用的工具。它们广泛流行的部分原因在于，它们通常能耐受大量官能团，这使得它们可用于广泛的应用中。然而，多年来钯催化偶联过程的一个主要限制是芳基氯的反应活性较差，从成本和可得性的角度来看，芳基氯比相应的溴化物、碘化物和三氟甲磺酸酯更具吸引力。传统的钯/三芳基膦催化剂仅对某些活化的芳基氯（例如，杂芳基氯和带有吸电子基团的底物）的偶联有效，而一般对芳基氯无效。自1998年以来，多个研究小组描述了应对这一挑战的重大进展；基于体积庞大、富电子的膦和卡宾的催化剂已被证明特别温和且通用。本综述总结了钯催化芳基氯偶联领域的开创性早期工作和令人兴奋的最新进展。
