Abstract:A number of 3-bromo-5,6-dihydro-4H-1,2-oxazine Noxides have been synthesized and subjected to [3+2] cycloaddition with alkenes affording various types of products: 3-vinyloxazolines, isoxazoline N-oxides, and 3-functionalized 1,2-oxazine N-oxides.
“…Bromonitrostyrenes can be applied for the construction of 3bromo-5,6-dihydro-4H-1,2-oxazine N-oxides (Scheme 11). 40 An alkene was used as a coupling partner and the cyclization reaction was performed in the presence of SnCl bicycle[3,2,1] octane of 1,2-diones 25 from nitroalkenes and 1 1,2cyclohexadione 24 (Scheme 12). 41 a-Bromonitroalkene 1 in a domino Michael-Henry reaction with diketone 24 can furnish product 25 with two syn and anti isomers.…”
Section: Metal-catalyzed Transformations Of Bromonitrostyrenesmentioning
confidence: 99%
“…Bromonitrostyrenes can be applied for the construction of 3-bromo-5,6-dihydro-4 H -1,2-oxazine N -oxides ( Scheme 11 ). 40 An alkene was used as a coupling partner and the cyclization reaction was performed in the presence of SnCl 4 or TiCl 2 (O i Pr) 2 as a Lewis acid catalyst. (4 + 2)-Cycloaddition of alkene to bromonitrostyrene was sensitive to the reaction conditions, where an increase in temperature or time led to 3-chloro-1,2-oxazine N -oxide as byproduct.…”
Section: Transformations Of Bromonitrostyrenesmentioning
In this work, we have described the use of α-bromonitrostyrenes in the synthesis of a wide variety of carbocyclic and heterocyclic compounds under organocatalysis, metal catalysis, and base-catalysis systems as well as catalyst-free reactions.
“…Bromonitrostyrenes can be applied for the construction of 3bromo-5,6-dihydro-4H-1,2-oxazine N-oxides (Scheme 11). 40 An alkene was used as a coupling partner and the cyclization reaction was performed in the presence of SnCl bicycle[3,2,1] octane of 1,2-diones 25 from nitroalkenes and 1 1,2cyclohexadione 24 (Scheme 12). 41 a-Bromonitroalkene 1 in a domino Michael-Henry reaction with diketone 24 can furnish product 25 with two syn and anti isomers.…”
Section: Metal-catalyzed Transformations Of Bromonitrostyrenesmentioning
confidence: 99%
“…Bromonitrostyrenes can be applied for the construction of 3-bromo-5,6-dihydro-4 H -1,2-oxazine N -oxides ( Scheme 11 ). 40 An alkene was used as a coupling partner and the cyclization reaction was performed in the presence of SnCl 4 or TiCl 2 (O i Pr) 2 as a Lewis acid catalyst. (4 + 2)-Cycloaddition of alkene to bromonitrostyrene was sensitive to the reaction conditions, where an increase in temperature or time led to 3-chloro-1,2-oxazine N -oxide as byproduct.…”
Section: Transformations Of Bromonitrostyrenesmentioning
In this work, we have described the use of α-bromonitrostyrenes in the synthesis of a wide variety of carbocyclic and heterocyclic compounds under organocatalysis, metal catalysis, and base-catalysis systems as well as catalyst-free reactions.
Bromonitroalkenes are useful molecules in synthetic organic chemistry. They are mainly prepared from nitroalkenes via bromination reaction. In this review, the application of bromonitroalkenes as partner in the reaction with...
“…Following previous studies on the [4 + 2]-cyclofragmentation of 1,2-oxazine N -oxides to unsaturated oxime derivatives, 14 as well as reactions of 1,2-oxazine N -oxides with arynes, 15 we envisioned 3-halo-substituted 1,2-oxazine N -oxides as viable surrogates of unsaturated nitrile oxides. It relies on the possibility of base-promoted cyclofragmentation/elimination of HBr (Scheme 1, (4)).…”
The reaction of 3-halo-5,6-dihydro-4H-1,2-oxazine N-oxides with arynes was studied. Arynes were generated from o-silylaryl triflates and underwent consecutive [3+2]-cycloaddition/[4+2]-cycloreversion with N-oxides leading to substituted 3-vinyl-benzisoxazoles in high yields. In the...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.