Mechanistic Studies on a Cooperative NHC Organocatalysis/Palladium Catalysis System: Uncovering Significant Lessons for Mixed Chiral Pd(NHC)(PR<sub>3</sub>) Catalyst Design
作者:Chang Guo、Daniel Janssen-Müller、Mirco Fleige、Andreas Lerchen、Constantin G. Daniliuc、Frank Glorius
DOI:10.1021/jacs.7b00462
日期:2017.3.29
detailed investigation of the catalytically active palladium species pointed toward a dual role of the NHC acting as an organocatalyst and forming a novel mixed ligand Pd/NHC/phosphine complex. The catalytically active Pd/NHC/phosphine complex represents a new class of chiral palladium catalyst. Remarkably, phosphine plays a crucial role in this transformation. These complexes could be characterized by
对高度对映选择性 Pd(PPh3)4/NHC 催化的乙烯基苯并恶嗪酮和烯醛环化的机理进行了全面研究。对反应顺序的研究支持假定的协同催化。有趣的是,对催化活性钯物种的详细研究表明,NHC 具有双重作用,既可作为有机催化剂,又可形成新型混合配体 Pd/NHC/膦复合物。具有催化活性的 Pd/NHC/膦配合物代表了一类新的手性钯催化剂。值得注意的是,膦在这种转变中起着至关重要的作用。