1, 3-Dipolar cycloaddition reaction of trimethylstannylacetylene with nitrile oxides yielded 3-substituted 5-(trimethylstannyl)isoxazoles. On the other hand, the same reaction of (trimethylstannyl)phenylacetylene, -1-hexyne, and -(trimethylsilyl)acetylene gave 3, 5-disubstituted 4-(trimethylstannyl)isoxazoles almost regioselectively. The regioselectivity of the cycloaddition reaction is interpreted by application of the frontier-electron theory.
Gold(III)-Catalyzed Synthesis of Isoxazoles by Cycloisomerization of α,β-Acetylenic Oximes
作者:P. Perumal、C. Praveen、A. Kalyanasundaram
DOI:10.1055/s-0029-1219342
日期:2010.3
β-acetylenic oximes leading to substituted isoxazoles was achieved using AuCl 3 as catalyst, under moderate reaction conditions. The reaction can be applied to various acetylenic oximes and gives good to excellent yields. The methodology is amenable for the selective synthesis of 3-substituted, 5-substituted or 3,5-disubstituted isoxazoles by simply altering the substituents on the acetylenic oximes.
Silyl isoxazolines-2: synthesis, structure and properties
作者:E. Lukevics、V. Dirnens、A. Kemme、J. Popelis
DOI:10.1016/0022-328x(96)06358-9
日期:1996.8
Silyl isoxazolines have been synthesized by [2 + 3] cycloaddition reaction of nitrileoxides and silylnitronates to vinyl- and allylsilanes. The direction of the cycloaddition reaction of nitrileoxides to trialkoxyvinylsilanes has been shown to depend on the nature of the substituents on silicon and on the method used to generate the nitrileoxides. The addition of silyl esters of aci-nitromethane
Silylated β-enaminones as precursors in the regioselective synthesis of silyl pyrazoles
作者:Mariola Calle、Luis A. Calvo、Alfonso González-Ortega、Ana M. González-Nogal
DOI:10.1016/j.tet.2005.10.001
日期:2006.1
Silyl β-enaminones have been synthesized by reductive cleavage of 5-silyl, 3-, 4- and 5-silylmethylisoxazoles.These versatile synthons bearing different silyl groups in various positions of the enaminoketonic system are of great interest in the regioselective synthesis of 3- or 5-silylpyrazoles and 3-, 4- or 5-silylmethylpyrazoles, which can serve as building blocks in heterocyclic chemistry.
Silylated azolium salts and their applications in the synthesis of azolines and β-enaminoketones bearing allyl-, vinyl-, and acylsilane or α-silylketone units
作者:Ana M. González-Nogal、Mariola Calle
DOI:10.1016/j.tet.2009.01.114
日期:2009.7
Differently silylated 3- or 4-isoxazolines and 3-pyrazolines, bearing versatile vinyl- or allylsilane moieties in various positions of the heterocyclic system, have been synthesized starting from new silylazolium salts by reduction with metal complex hydrides or alkylation with organolithium reagents. On the other hand, the reductive ring-opening of silylated isoxazolium salts with lithium dimethylcuprate