Replacing Conventional Carbon Nucleophiles with Electrophiles: Nickel-Catalyzed Reductive Alkylation of Aryl Bromides and Chlorides
作者:Daniel A. Everson、Brittany A. Jones、Daniel J. Weix
DOI:10.1021/ja301769r
日期:2012.4.11
general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (−OH,
Roles reversed: An efficient cobalt‐catalyzed electrophilic amination of arylzinc reagents has been achieved. A variety of functionalized arylzincs and N‐chloroamines were coupled under mild conditions (see scheme). Both secondary and tertiary arylamines were obtained in moderate to excellent yields.
Copper Powder and Pd(II) Salts Triggered One-Pot Aromatic Halide Homocoupling via a Radical Pathway
作者:Chen Li、Yumeng Shi、Quan Chen、Kun Zhang、Guang Yang
DOI:10.1021/acs.joc.2c02717
日期:2023.2.17
this work, a bimetallic system was demonstrated, referring to stoichiometric copper powder in the presence of a catalytic amount of Pd(OAc)2, which contributed to delivering various symmetric/asymmetric (sp2)C–(sp2)C species. It has been proposed that the coupling process might be promoted via radicals produced by redox between Cu(0) and Pd(IV) species in the heating system. Increasing examples demonstrated
An Improved Synthesis of the Free Base and Diglycolate Salt of CEP-33779; A Janus Kinase 2 Inhibitor
作者:Daniel V. Levy、Joseph A. Sclafani、Roger P. Bakale
DOI:10.1021/acs.oprd.6b00311
日期:2016.12.16
CEP-33779 is a triazole that has been reported to show highly selective inhibition of Janus kinase 2 (JAIC2). An efficient process to form CEP-33779 will be presented that uses multiple palladium couplings to provide the drug substance in a convergent manner. The existing medicinal chemistry route was modified to avoid chromatographic purification, improve safety, and utilize palladium ligands which are available in quantities amenable to scale-up. Challenges faced during the development of the new process included optimization of conditions for Buchwald-Hartwig and Suzuki couplings, control of homocoupled impurities and removal of residual palladium. In addition, a screen of conditions to form a diglycolate salt of the parent compound are also presented.
New Chemical Synthesis of Functionalized Arylzinc Compounds from Aromatic or Thienyl Bromides under Mild Conditions Using a Simple Cobalt Catalyst and Zinc Dust
A new chemical method for the preparation of arylzinc intermediates is described in acetonitrile, on the basis of the activation of aryl bromides by low-valent cobalt species arising from the reduction of cobalt halide by zinc dust. This procedure allows for the synthesis of a variety of functionalized aryl- and thienylzinc species in good to excellent yields. The versatility and the simplicity of that original method represent an alternative to most known procedures.