通过无环硝酮与游离的和铂（II）配位的有机腈反应立体定向合成多取代的E-烯烃。
Stereospecific synthesis of polysubstituted E-olefins by reaction of acyclic nitrones with free and platinum(II) coordinated organonitriles.
作者信息
Lasri Jamal, Charmier M Adília Januario, Haukka Matti, Pombeiro Armando J L
机构信息
Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Avenida Rovisco Pais, 1049-001, Lisbon, Portugal.
出版信息
J Org Chem. 2007 Feb 2;72(3):750-5. doi: 10.1021/jo061659b.
Free nitriles NCCH2R (1a R = CO2Me, 1b R = SO2Ph, and 1c R = COPh) with an acidic alpha-methylene react with acyclic nitrones -O+N(Me)=C(H)R' (2a R' = 4-MeC6H4 and 2b R' = 2,4,6-Me3C6H2), in refluxing CH2Cl2, to afford stereoselectively the E-olefins (NC)(R)C=C(H)R' (3a-3c and 3a'-3c'), whereas, when coordinated at the platinum(II) trans-[PtCl2(NCCH2R)2] complexes (4a R = CO2Me and 4b R = Cl), they undergo cycloaddition to give the (oxadiazoline)-PtII complexes trans-[PtCl2{N=C(CH2R)ON(Me)C(H)R'}2] (R = CO2Me, Cl and R' = 4-MeC6H4, 2,4,6-Me3C6H2) (5a-5d). Upon heating in CH2Cl2, 5a affords the corresponding alkene 3a. The reactions are greatly accelerated when carried out under focused microwave irradiation, particularly in the solid phase (SiO2), without solvent, a substantial increase of the yields being also observed. The compounds were characterized by IR and 1H, 13C, and 195Pt NMR spectroscopies, FAB+-MS, elemental analyses and, in the cases of the alkene (NC)(CO2Me)C=C(H)(4-MeC6H4) 3a and of the oxadiazoline complex trans-[PtCl2{N=C(CH2Cl)ON(Me)C(H)(4-C6H4Me)}2] 5c, also by X-ray diffraction analyses.
具有酸性α-亚甲基的游离腈NCCH₂R（1a，R = CO₂Me；1b，R = SO₂Ph；1c，R = COPh）与无环硝酮-O⁺N（Me）=C（H）R'（2a，R' = 4-MeC₆H₄；2b，R' = 2,4,6-Me₃C₆H₂）在回流的二氯甲烷中反应，立体选择性地生成E-烯烃（NC）（R）C=C（H）R'（3a - 3c和3a' - 3c'），然而，当它们与铂（II）反式-[PtCl₂（NCCH₂R）₂]配合物（4a，R = CO₂Me；4b，R = Cl）配位时，会发生环加成反应生成（恶二唑啉）-PtII配合物反式-[PtCl₂{N=C（CH₂R）ON（Me）C（H）R'}₂]（R = CO₂Me，Cl；R' = 4-MeC₆H₄，2,4,6-Me₃C₆H₂）（5a - 5d）。在二氯甲烷中加热时，5a生成相应的烯烃3a。当在聚焦微波辐射下进行反应时，反应速度大大加快，特别是在无溶剂的固相中（SiO₂），产率也有显著提高。这些化合物通过红外光谱、¹H、¹³C和¹⁹⁵Pt核磁共振光谱、快原子轰击正离子质谱、元素分析进行表征，对于烯烃（NC）（CO₂Me）C=C（H）（4-MeC₆H₄）3a和恶二唑啉配合物反式-[PtCl₂{N=C（CH₂Cl）ON（Me）C（H）（4-C₆H₄Me）}₂] 5c还通过X射线衍射分析进行表征。
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