Horbaczewskyj Christopher S, Fairlamb Ian J S
University of York, Heslington, York, North Yorkshire, YO10 5DD, United Kingdom.
Org Process Res Dev. 2022 Aug 19;26(8):2240-2269. doi: 10.1021/acs.oprd.2c00051. Epub 2022 Jul 11.
This Review examines parts per million (ppm) palladium concentrations in catalytic cross-coupling reactions and their relationship with mole percentage (mol %). Most studies in catalytic cross-coupling chemistry have historically focused on the concentration ratio between (pre)catalyst and the limiting reagent (substrate), expressed as mol %. Several recent papers have outlined the use of "ppm level" palladium as an alternative means of describing catalytic cross-coupling reaction systems. This led us to delve deeper into the literature to assess whether "ppm level" palladium is a practically useful descriptor of catalyst quantities in palladium-catalyzed cross-coupling reactions. Indeed, we conjectured that many reactions could, unknowingly, have employed low "ppm levels" of palladium (pre)catalyst, and generally, what would the spread of ppm palladium look like across a selection of studies reported across the vast array of the cross-coupling chemistry literature. In a few selected examples, we have examined other metal catalyst systems for comparison with palladium.
本综述考察了催化交叉偶联反应中百万分之一（ppm）钯的浓度及其与摩尔百分比（mol%）的关系。历史上，催化交叉偶联化学领域的大多数研究都集中在（预）催化剂与限量试剂（底物）之间的浓度比，以摩尔百分比表示。最近的几篇论文概述了使用“ppm级”钯作为描述催化交叉偶联反应体系的另一种方式。这促使我们更深入地研究文献，以评估“ppm级”钯是否是钯催化交叉偶联反应中催化剂用量的一个实际有用的描述符。事实上，我们推测许多反应可能在不知不觉中使用了低“ppm级”的钯（预）催化剂，一般来说，在大量交叉偶联化学文献报道的一系列研究中，ppm钯的分布情况会是怎样的。在一些选定的例子中，我们研究了其他金属催化剂体系以与钯进行比较。
