strategy to turnover H‐MII‐X complexes has enabled both intra‐ and intermolecular Mizoroki–Heck (MH)‐type reactions of arylcyanides that are challenging to realize under traditional, basic conditions. Initially, a cascade carbonickelation/MH reaction of 2‐cyanostyrenes was achieved using a key alkyne transfer hydrocyanation step. Mechanistic experiments supported the proposed catalytic cycle, including
一种新的转移H-M II - X配合物的转移加氢官能化策略,使芳基氰化物的分子内和分子间Mizoroki-Heck(MH)型反应成为可能,这在传统的基本条件下很难实现。最初,使用关键的炔烃转移氢氰化步骤实现了2-氰基苯乙烯的级联羰基化/ MH反应。机械实验支持了拟议的催化循环,包括促成转移的转移氢氰化步骤。然后将反应性扩展至苄腈和苯乙烯的分子间MH反应。
Synthesis of Stilbenes by Rhodium-Catalyzed Aerobic Alkenylation of Arenes via C–H Activation
作者:Xiaofan Jia、Lucas I. Frye、Weihao Zhu、Shunyan Gu、T. Brent Gunnoe
DOI:10.1021/jacs.0c03935
日期:2020.6.10
Arenealkenylation is commonly achieved by late transition metal-mediated C(sp2)-C(sp2) cross-coupling, but this strategy typically requires prefunctionalized substrates (e.g., with halides or pseudohalides) and/or the presence of a directing group on the arene. Transition metal-mediated areneC-Hactivation and alkenylation offers an alternative method to functionalize arene substrates. Herein, we
Ligand- and copper-free Sonogashira and Heck couplings of (Het)aryl chlorides and bromides catalyzed by palladium nanoparticles supported on in situ generated Al(OH)<sub>3</sub>
ligand- and copper-free Sonogashirareaction of (Het)aryl halides (Br and Cl) with various terminal alkynes and the Heck coupling of (Het)aryl halides (Br and Cl) with a series of olefins, catalyzed by palladiumnanoparticles supported on newly generated Al(OH)3, were developed. The catalyst can be readily recovered and reused 6 times without significant loss of activity and palladium leaching.
Three pyrazolyl-functionalized N-heterocyclic carbene (NHC) palladium complexes based on 1-[2-(pyrazol-1-yl)phenyl]imidazole have been synthesized and characterized by physico-chemical and spectroscopic methods, and the structures of two of the complexes have been confirmed by single-crystal X-ray diffraction. The pyrazolyl-functionalized NHCs act as chelating N,C-bidentate ligands in these three complexes. Catalytic tests have proved that these complexes exhibit highly effective catalytic activity for the Suzuki–Miyaura and Mizoroki–Heck coupling reactions in water or aqueous/organic media under air. The substituents on the pyrazolyl ring exert different influences on the catalytic activity of the complexes in these coupling reactions.
Pd(II)-catalyzed oxidative Heck-type reaction of triarylphosphines with alkenes via carbon–phosphorus bond cleavage
作者:Ming-Tao Ma、Jian-Mei Lu
DOI:10.1016/j.tet.2013.01.025
日期:2013.3
A Pd(II)-catalyzed oxidative Heck-type reaction of triarylphosphines with alkenes via carbon–phosphorusbondcleavage was reported. Under the optimal reaction conditions, most reactions proceeded smoothly to give the expected coupling products in acceptable to high yields.