Methyl Ketone Oxime Esters as Nucleophilic Coupling Partners in Pd-Catalyzed C–H Alkylation and Application in the Synthesis of Isoquinolines
作者:Zhi-Wei Zhang、Aijun Lin、Jiong Yang
DOI:10.1021/jo5010586
日期:2014.8.1
excellent coupling partners for C(sp2)–C(sp3) bond formation via Pd-catalyzed aromatic C–H activation. This transformation forms the basis of an approach to regioselectively synthesize substituted isoquinolines via coupling with aryloxime esters. Our mechanistic studies suggested that the reaction proceeded through Pd(II)-catalyzed aromatic C–H activation, tautomerization, and a 1,3-shift of the palladacycle-ligated
Cp*Co
<sup>III</sup>
Catalyzed Site‐Selective CH Activation of Unsymmetrical
<i>O</i>
‐Acyl Oximes: Synthesis of Multisubstituted Isoquinolines from Terminal and Internal Alkynes
The synthesis of isoquinolines by site‐selective CHactivation of O‐acyl oximes with a Cp*CoIII catalyst is described. In the presence of this catalyst, the CHactivation of various unsymmetrically substituted O‐acyl oximes selectively occurred at the sterically less hindered site, and reactions with terminal as well as internal alkynes afforded the corresponding products in up to 98 % yield. Whereas
描述了通过使用Cp * Co III催化剂对O-酰基肟进行定点CH活化来合成异喹啉。在这种催化剂的存在下,各种不对称取代的O-酰基肟的CH活化选择性地发生在空间较少受阻的位点,并且与末端炔烃和内部炔烃的反应提供了相应的产物,收率高达98%。尽管Cp * Co III系统催化的反应以高位点选择性(15:1至20:1)进行,但使用了相应的Cp * Rh III当使用不对称的O-酰基肟和末端炔烃时,催化剂导致较低的选择性和/或收率。氘标记研究表明,在Cp * Co III和Cp * Rh III催化下,CH活化步骤的位点选择性存在明显差异。
Palladium-Catalyzed C–H Functionalization of Aromatic Oximes: A Strategy for the Synthesis of Isoquinolines
reaction of oximes with vinyl azides or homocoupling of oximes is reported. Oximes could serve as a directing group and an internal oxidant in the transformation. This reaction features good functional group tolerance and provides a useful protocol for the synthesis of different kinds of isoquinolines under mild conditions. Some control experiments and 15N isotope labeling experiments were conducted for