3-Ethoxycyclobutanones reacted with pyridines, quinolines, and isoquinolines to give the corresponding formal [4+2] cycloadducts, 9a-hydro-2H-quinolizin-2-one derivatives, by using Me3SiOTf in acetonitrile. Cycloaddition of 3-ethoxy-2-monoalkylcyclobutanones to 5-nitroquinoline or 4-cyanopyridine proceeded stereoselectively.
Lewis Acid-Mediated [3+3] Annulation for the Construction of Substituted Pyrimidine and Pyridine Derivatives
作者:Yao Zhou、Zhonghe Tang、Qiuling Song
DOI:10.1002/adsc.201601386
日期:2017.3.20
A direct and single‐step procedure towards substituted pyrimidine and pyridine derivatives via Lewis acid‐promoted [3+3] annulation between 3‐ethoxycyclobutanones and enamines or amidines is presented. Diverse substituted pyrimidine and pyridine derivatives were obtained in good to high yields with a wide substrate scope.
A Co-catalyzed highly chemo- and regio-selective nitration of C(sp3)-H was developed. Diverse aliphaticnitrocompounds were obtained in good yields, using t-BuONO as nitrating reagent. Specific nitration of C(sp3)-H instead of C(sp2)-H was achieved via a radical process rather than concerted metalation-deprotonation.
Synthesis of three-dimensional fused and spirocyclic oxygen-containing cyclobutanone derivatives
作者:Sergey V. Ryabukhin、Kateryna I. Fominova、Dmitriy A. Sibgatulin、Oleksandr O. Grygorenko
DOI:10.1016/j.tetlet.2014.11.050
日期:2014.12
approach to fused and spirocyclic oxygen-containing cyclobutanone derivatives based on ketene [2+2] cycloaddition with vinyl ethers is described. Using alicyclic chloroanhydrides as ketene sources as well as cyclic vinyl ethers in the reaction resulted in the formation of three-dimensional conformationally restricted building blocks of interest to medicinal chemistry and organic synthesis. In particular
Formal [4+2] cycloaddition of 3-ethoxycyclobutanones with azo compounds
作者:Yusuke Shima、Jun-ichi Matsuo
DOI:10.1016/j.tetlet.2016.07.087
日期:2016.9
with EtAlCl2, and intermolecular formal [4+2] cycloaddition of the zwitterionic intermediate proceeded with azobenzenes to give 2,3-dihydro-pyridazin-4(1H)-ones after elimination of ethanol. Regioselectivity for cycloaddition of unsymmetrical azobenzenes, ring contraction and chemoselective reduction of 2,3-dihydro-pyridazin-4(1H)-ones, and [4+2] cycloaddition to 4-phenyl-1,2,4-triazolin-3,5-dione are