Transition-Metal-Free β-C–H Bond Carbonylation of Enamides or Amides with a Trifluoromethyl Group as CO Surrogate for the Synthesis of 1,3-Oxazin-6-ones
作者:Ping Song、Peng Yu、Jin-Shun Lin、Yiqun Li、Ning-Yuan Yang、Xin-Yuan Liu
DOI:10.1021/acs.orglett.7b00178
日期:2017.3.17
A cascade β-C–H bond trifluoromethylation/C(sp3)–F bond activation/hydrolysis reaction of enamides with Togni’s reagent has been disclosed. This formal C–H bond carbonylation reaction utilizes the CF3 group as a CO surrogate to provide an efficient approach to 1,3-oxazin-6-ones in satisfactory yields. Furthermore, CF3-containing 1,3-oxazin-6-ones could also be accessed using this method by using alkenyl
Gold-catalyzed formal [4π + 2π]-cycloadditions of propiolate derivatives with unactivated nitriles
作者:Somnath Narayan Karad、Wei-Kang Chung、Rai-Shung Liu
DOI:10.1039/c5sc01950h
日期:——
Gold-catalyzed hetero-[4π + 2π]-cycloadditions of tert-butyl propiolates with unactivated nitriles are described. This new finding enables a one-pot gold-catalyzed synthesis of highly substituted pyridines.
Ring-enlargemen of isoxazol-5-ones to 1,3-oxazin-6-ones
作者:Francesco Risitano、Giovanni Grassi、Francesco Foti、Francesco Caruso、Giacomo Lo Vecchio
DOI:10.1039/p19790001522
日期:——
Isoxazol-5-ones undergo ring-enlargement by reaction with nitrile oxides to give 1,3-oxazin-6-ones. The mechanism is discussed. Some chemical transformations of the oxazinone ring are described.
NHC-catalyzed single electron transfer (SET) between aldehydes and trihalomethyl reagents, followed by the addition of trihalomethyl radicals to vinyl azides, a denitrogenated transformation into iminylradicals, a C–N radical coupling of iminylradicals and ketyl radicals, and a base-controlled dehalogenative cyclization.