title: N-heterocyclic carbene-catalyzed cascade annulation reaction of o-vinylarylaldehydes with nitrosoarenes: one-step assembly of functionalized 2,3-benzoxazin-4-ones.
abstract: The NHC-catalyzed reactions of ortho electron-deficient vinyl substituted arylaldehydes with nitrosoarenes were studied. The reactions produced multifunctional 2,3-benzoxazin-4-ones in good to excellent yields via a cascade aza-benzoin reaction between aldehyde and nitroso groups followed by an intramolecular oxo-Michael addition. The resulting 1-acetate substituted 2,3-benzoxazinones were transformed into a new type of β-hydroxycarboxylate derivatives or 3-oxo-1-isobenzofuranacetates, respectively, under different reductive conditions. This work not only provides a simple and efficient method for the construction of multifunctional 2,3-benzoxazin-4-ones of potential pharmacological interest, but also expands the application of NHC-catalyzed cascade reactions in the formation of carbon-heteroatom and heteroatom-heteroatom bonds.
authors.affiliation: College of Chemistry, Beijing Normal University, Beijing 100875, China.
authors.forename: Zhong-Xin
authors.initials: ZX
authors.lastname: Sun
authors.forename: Ying
authors.initials: Y
authors.lastname: Cheng