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.
Herein, we report a novel synthesis of 1,3‐oxazin‐6‐onesfrom enamides with CO2 through C—H carboxylation and one‐potcyclization. This transition‐metal‐free and redox‐neutral process features broad substrate scope, good functional group tolerance and facile product derivatization. The nucleophilic attack to CO2 from the electron‐rich alkene is demonstrated for this reaction.