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

Abstract

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 N-ethylamides involving the functionalization of one C_sp2-H, one C_sp3-H, one C_sp2-H, and three C_sp3-F bonds. The broad substrate scope of this method enables access to synthetically or pharmaceutically important compounds, which are difficult to access by known methods.