Additive effects on palladium-catalyzed deprotonative-cross-coupling processes (DCCP) of sp3 C-H bonds in diarylmethanes
Additive effects on palladium-catalyzed deprotonative-cross-coupling processes (DCCP) of sp3 C-H bonds in diarylmethanes
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DOI：
10.1039/c2sc21673f
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发表时间：
2013-01-01
期刊：
影响因子：
8.4
通讯作者：
Walsh, Patrick J.
中科院分区：
文献类型：
--
作者：
Bellomo, Ana;Zhang, Jiadi;Walsh, Patrick J.
钯催化的交叉偶联反应已成为现代有机化学中最有用的工具之一。目前实现芳烃和杂芳烃的sp（3）C-H键的直接官能化的方法通常采用具有适当放置的导向基团的底物以实现反应性。然而，在不存在导向基团的情况下，弱酸性sp3 C-H键的分子间芳基化方法的实例仍然有限。本文描述了添加剂在室温下Pd催化的二芳基甲烷与芳基溴的sp3 C-H键的去质子交叉偶联过程（DCCP）中的应用。这些研究导致开发了四种新的高效Pd催化的DCCP，其使用添加剂，使得能够以良好至优异的产率产生一系列空间和电子上不同的含芳基和杂芳基的三芳基甲烷。使用高通量实验（HTE）进行添加剂鉴定和所有反应条件（添加剂加载、溶剂和温度）的优化。本文概述的方法预期可推广到涉及弱酸性C-H键的去质子化的其他C-H官能化反应。
Palladium-catalyzed cross-coupling reactions have become one of the most useful tools in modern organic chemistry. Current methods to achieve direct functionalization of sp(3) C-H bonds of arenes and heteroarenes often employ substrates with appropriately placed directing groups to enable reactivity. Examples of intermolecular arylation methods of weakly acidic sp3 C-H bonds in the absence of directing groups, however, are still limited. We describe herein a study on the use of additives in Pd-catalyzed deprotonative-cross-coupling processes (DCCP) of sp3 C-H bonds of diarylmethanes with aryl bromides at room temperature. These studies resulted in development of four new efficient Pd-catalyzed DCCP using additives that enabled the generation of a range of sterically and electronically diverse aryl- and heteroaryl containing triarylmethanes in good to excellent yields. Additive identification and optimization of all reaction conditions (additive loading, solvent and temperature) were performed using high-throughput experimentation (HTE). The approach outlined herein is expected to be generalizable to other C-H functionalization reactions involving the deprotonation of weakly acidic C-H bonds.