Stille Coupling of Alkynyl Stannane and Aryl Iodide, a Many-Pathways Reaction: The Importance of Isomerization
作者:Mónica H. Pérez-Temprano、Ana M. Gallego、Juan A. Casares、Pablo Espinet
DOI:10.1021/om100978w
日期:2011.2.14
The kinetics of the Stille reaction between C6Cl2F3I and PhCCSnBu3 have been studied for the whole catalytic system and for transmetalations as separate steps. The use of (trifluorodichlorophenyl)palladium derivatives slows down the reactions and allows for the observation of the intermediates cis- and trans-[Pd(C6Cl2F3)I(PPh3)2]. The first is formed in the oxidative addition step and isomerizes to
C 6 Cl 2 F 3 I和PhCCSnBu 3之间的Stille反应动力学已针对整个催化系统和作为单独步骤的重金属化进行了研究。(三氟二氯苯基)钯衍生物的使用减慢了反应的速度,并允许观察到中间体顺式和反式[Pd(C 6 Cl 2 F 3)I(PPh 3)2]。第一个在氧化加成步骤中形成并异构化为第二个。两者均被研究为整个循环的催化剂。动力学研究比较了每种异构体的重金属化步骤的相关性。竞争的金属转移物同时产生顺式和反式-[Pd(C 6 Cl 2 F 3)(PhCC)(PPh 3)2 ]。前者经历了非常快的C-C耦合,而第二者由于极慢的异构化而积累在溶液中。因此,该系统是对Stille反应中竞争途径的影响及其对催化过程性能的影响的案例研究。
Problematic Ar<sup>F</sup>–Alkynyl Coupling with Fluorinated Aryls. From Partial Success with Alkynyl Stannanes to Efficient Solutions via Mechanistic Understanding of the Hidden Complexity
作者:Guillermo Marcos-Ayuso、Marconi N. Peñas-Defrutos、Ana M. Gallego、Max García-Melchor、Jesús M. Martínez-Ilarduya、Pablo Espinet