Oxidation of aromatic compounds: XV. Oxidation of arylacetylenes in a system HF-PbO2
摘要:
The oxidation of symmetrically substituted diarylacetylenes ArC CAr (Ar=C6H4R) containing strong electron-withdrawing groups R=4-COMe, 4-CO2Me, 3-CO2Et, and 4-NO2 in a system HF-PbO2 at -10 divided by-20 degrees C led within 0.5-3 h to the formation of Z,Z-1,2,3,4-tetrakis(aryl)-1,4-difluorobuta-1,3-dienes ArFC=C(Ar) ( Ar)C=CFAr. The butadiene structures obtained exist in solutions as s-cis- and s-trans-conformers and in the crystalline state are present in the stable s-cis-form.
terminal alkynes, and internal alkynes is reported. The reaction is initiated with a chemoselective copper-catalyzed azide alkyne cycloaddition (CuAAC) followed by a palladium-catalyzed incorporation of an internal alkyne. The simple one-pot procedure introduces C–H functionalization to the growing field of multicomponent multicatalytic reactions ((MC)2R). With inexpensive CuI and the Herrmann–Beller
报告了一种可靠的方法,用于有机叠氮化物,末端炔烃和内部炔烃的双金属催化组合。该反应通过化学选择性铜催化的叠氮化物炔烃环加成反应(CuAAC)引发,然后钯催化的内部炔烃掺入。简单的一锅法将C–H功能化引入了多组分多催化反应((MC)2 R)的不断发展的领域。用廉价的CuI和Herrmann-Beller钯环烷作为催化剂,可生成四个键和两个杂环,其中HI为唯一的副产物。所有组分的广泛应用范围展示了这种多功能的转变,从而导致了一类新型的全取代多环三唑。1个1 H NMR和氘标记研究为洞悉铜和钯步骤的速率差异提供了见识。
Synthesis of Phenalenyl-Fused Pyrylium Cations: Divergent C−H Activation/Annulation Reaction Sequence of Naphthalene Aldehydes with Alkynes
作者:Jiangliang Yin、Meiling Tan、Di Wu、Ruyong Jiang、Chengming Li、Jingsong You
DOI:10.1002/anie.201708127
日期:2017.10.9
Shell out: The rhodium-catalyzed C−H activation/annulation sequence of naphthalene-type aldehydes with internal alkynes has been developed to provide access to phenalenyl-fused pyrylium cations. Also disclosed is the open-shell radical character of the reduced products.
Alkyne metathesis with simple catalyst systems: High yield dimerization of propynylated aromatics; scope and limitations
作者:Neil Gregory Pschirer、Uwe H.F. Bunz
DOI:10.1016/s0040-4039(99)00282-8
日期:1999.3
yield dimerization of propynylated benzenes and propynylnaphthalene by a mixture of Mo(CO)6 and 4-chlorophenol at 140 °C in 1,2-dichlorobenzene is reported to give the corresponding disubstituted alkynes. The scope and limitation of the reaction and the influence of substitution pattern and substitution type are discussed. Oxygen or nitrogen carrying substrates metathesize in moderate to good yields
substituent is hardly imaginable in the confinement of the crystal. Therefore, the geometrically easier ‘hula-twist’ (HT) mechanism with its movements primarily in the molecular plane provides a viable mechanistic alternative for the cis–trans isomerization. The solid-state mechanism of the reaction was studied by x-ray and atomic force microscopy (AFM) analyses. Face-selective efflorescence formed a
Rhodium<sup>III</sup>-catalyzed remote difunctionalization of arenes assisted by a relay directing group
作者:Lincong Sun、Yuyao Zhao、Bingxian Liu、Junbiao Chang、Xingwei Li
DOI:10.1039/d2sc02205b
日期:——
Rhodium-catalyzed diverse tandem twofold C–H bond activation reactions of para-olefin-tethered arenes have been realized, with unsaturated reagents such as internal alkynes, dioxazolones, and isocyanates being the coupling partner as well as a relay directing group which triggers cyclization of the para-olefin group under oxidative or redox-neutral conditions. The reaction proceeded via initial ortho-C–H