β,β′-functionalized N,N-divinyl-N-trimethylsilyloxyamines via silylation of β-substituted aliphatic nitro compounds. The investigation of the mechanism of the process using selective trapping reagents
作者:Sema L. Ioffe、Il'ya M. Lyapkalo、Alexander A. Tishkov、Vitaliy M. Danilenko、Yuri A. Strelenko、Vladimir A. Tartakovsky
DOI:10.1016/s0040-4020(97)00831-4
日期:1997.9
good yields by silylation of nitro compounds XCH(R)CH2NO2 with N,O-bis(trimethylsilyl)acetamide. The mechanism of this reaction was studied by the example of silylation of methyl-3-nitropropionate using selective trapping reagents. Trimethylsilyl ester of the starting aci-nitro compound and methyl 2-nitroso acrylate were intercepted as consecutive intermediates. Thus, the silylation of β-functionalized
迄今未知的通式为[XC(R)= ch] 2 NOSiMe 3(X = CO 2 Me。CN。5-甲氧基羰基异恶唑啉-3-基的N,N-二乙烯基-N-三甲基甲硅烷基氧胺; R = H,Me,CH通过将硝基化合物XCH(R)CH 2 NO 2与N,O-双(三甲基甲硅烷基)乙酰胺甲硅烷基化,可以中等至良好的产率获得(Me)CO 2 Me)。通过使用选择性捕集剂对3-硝基丙酸甲酯进行甲硅烷基化的实例研究了该反应的机理。起始的三甲基甲硅烷酯ACI-硝基化合物和2-亚硝基丙烯酸甲酯被截取为连续的中间体。因此,可以将β-官能化的硝基化合物的甲硅烷基化作为通向实际上未知的β-取代的亚硝基烯烃XC(R)= CHNO的便利途径,其对于用作捕获剂的乙基乙烯基醚具有活性的1,3-杂二烯。
Preparation of Cyclic and Bicyclic β-Amino Acids Derivatives from Methyl 6-Ethoxy-5,6-dihydro-4H-1,2-oxazine-4-carboxylate
作者:Alexander A. Tishkov、Hans-Ulrich Reissig、Sema L. Ioffe
DOI:10.1055/s-2002-31908
日期:——
The readily available methyl 6-ethoxy-5,6-dihydro-4H-1,2-oxazine-4-carboxylate (1) was alkylated at C-4 and acylated at the nitrogen atom. 1,2-Oxazine 1 and the resulting new substituted 1,2-oxazines 2 and 3 were suitableprecursors for the preparation of derivatives of β-proline, nipecotic acid, as well as indolizine-6- and quinolizine-3-carboxylic acids.
Chemistry of β-Functionalized α-Nitroso Ethylenes. Methyl β-Nitroso Acrylate as Heterodienophile in [4 + 2]- Cycloaddition to Cyclic Dienes
作者:Alexander A. Tishkov、Il'ya M. Lyapkalo、Sema L. Ioffe、Yuri A. Strelenko、Vladimir A. Tartakovsky
DOI:10.1021/ol0057885
日期:2000.5.1
beta-Functionalized nitroso alkene 2, obtained from methyl beta-nitropropionate 1 and N,O-bis(trimethylsilyl)acetamide, can function as a good heterodienophile in Diels-Alder reactions, Therefore, 2 was trapped by cyclic dienes to give adducts 4 with the corresponding stereoselectivity, Cycloadduct 4a undergoes retro[4 + 2]-cycloaddition at 33 degrees C in solution; thus 4a can be used to generate nitroso alkene 2 in neutral medium. Cyclopentadiene reacts with adduct 4a according to an endo-[4 + 5]-cycloaddition scheme to give cycloadduct 5 in low yield.