The palladacyclic catalyst precursor received by ortho-palladation of ([1,1â²-biphenyl]-2-yloxy)diisopropyl-phosphine represents a highly active system for SuzukiâMiyaura cross-coupling reactions when used in neat water. An efficient, broadly applicable and sustainable aqueous protocol was developed using 2.5 eq. of Na2CO3 as base, allowing the reaction to be performed under air and at ambient temperature with Pd loadings of 0.04 mol%. Coupling products are obtained in high yields and excellent purity by simple filtration with no organic solvents needed throughout the whole reaction. A broad variety of functional groups are tolerated and a large number of substrates can be applied with this protocol. The crystal structure of the palladacyclic catalyst precursor is presented as well as investigations targeting the nature of catalyst activation and the active catalytic species.
通过使用无
水的[1,1'-
联苯]-2-基氧
二异丙基膦进行邻位
钯化得到的
钯环状催化剂前体,在纯
水体系中用于铃木-宫浦交叉偶联反应时表现出了高度活性。通过使用2.5当量的Na2CO3作为碱,我们开发了一种高效、广泛适用且可持续的
水相方法,使得反应能在空气中、常温下进行,且
钯的负载量仅为0.04摩尔百分比。通过简单的过滤即可获得高产率且纯度极佳的偶联产物,整个反应过程中无需任何有机溶剂。该方法对多种官能团具有耐受性,并且适用于大量不同底物。此外,本文还展示了
钯环状催化剂前体的晶体结构,并探讨了催化剂活化的本质以及活性催化物种的性质。