在5 bar H 2下,使用RuPHOX-Ru作为手性催化剂,对各种α-取代的丙烯酸进行不对称氢化,从而以高达99%的收率和99.9%ee的产率提供相应的手性α-取代的丙酸。该反应可以以克级进行,具有相对较低的催化剂负载量(最高5000 S / C),所得产物(97%,99.3%ee)可用作构建生物活性手性分子的关键中间体。该不对称方案已成功应用于二氢青蒿酸的不对称合成,这是抗疟疾药物青蒿素工业合成所需的关键中间体。
A facile and efficient approach for the synthesis of spirooxindoles has been developed via the coupling of spirocyclic C, C-palladacycles with CH2Br2. The key spirocyclic palladacycles are generated catalytically via intramolecular remote C–H activation. A range of spirooxindoles can be synthesized in good to excellent yields from readily available starting materials.
A highly efficient palladium‐catalyzed disilylation reaction of arylhalides through C−H activation has been developed for the first time. The reaction has broad substrate scope. A variety of arylhalides can be disilylated by three types of C−H activation, including C(sp2)−H, C(sp3)−H, and remote C−H activation. In particular, the reactions are also unusually efficient. The yields are essentially
A Pd(II)-catalyzed intermolecular C–H silylation reaction initiated by aminopalladation has been developed. The C–H bonds were activated by an alkyl Pd(II) species generated through aminopalladation and then disilylated with hexamethyldisilane to form disilylated indolines as the final products. The reaction provides a new method for the introduction of silylgroups into complex organic molecules.
Rhodium(III)-Catalyzed Intramolecular Annulation through CH Activation: Total Synthesis of (±)-Antofine, (±)-Septicine, (±)-Tylophorine, and Rosettacin
作者:Xianxiu Xu、Yu Liu、Cheol-Min Park
DOI:10.1002/anie.201204970
日期:2012.9.10
Annulation: The efficient synthesis of 3‐hydroxyalkyl isoquinolones and 6‐hydroxyalkyl 2‐pyridones is enabled through the intramolecular annulation of alkyne‐tethered hydroxamic esters (see scheme, Cp*=pentamethylcyclopentadienyl). The reaction features high regioselectivity, broad substrate scope, and excellent functional‐group tolerance, proceeds under mild reaction conditions with low catalyst loading
Silver-Catalyzed Decarboxylative Radical Addition/Cyclization of α,α-Difluoroarylacetic Acids with Acrylamides To Synthesize Difluorinated Oxindoles
作者:Yin-Long Li、Ji-Bo Wang、Xue-Lin Wang、Yang Cao、Jun Deng
DOI:10.1002/ejoc.201701248
日期:2017.11.2
silver-catalyzed decarboxylative radical addition/cyclizationreaction of α,α-difluoroarylacetic acids and acrylamides has been disclosed. The method provides a highly attractive approach to synthesize a series of difluorinated oxindoles that contain variousfunctional groups in moderate to good yields under mild conditions. Moreover, experimental studies reveal that the CF2 group of the α,α-difluoroarylacetic