Reactivity of a Seven-Membered Zirconacyclocumulene towards CN Multiple Bonds - Formation of Metallaheterocycles by Insertion of CN and C=N Groups
Reactivity of a Seven-Membered Zirconacyclocumulene towards CN Multiple Bonds - Formation of Metallaheterocycles by Insertion of CN and C=N Groups
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DOI：
10.1002/ejic.201402618
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发表时间：
2014-11-01
影响因子：
2.3
通讯作者：
Rosenthal, Uwe
中科院分区：
文献类型：
--
作者：
Burlakov, Vladimir V.;Becker, Lisanne;Rosenthal, Uwe
七元锆环枯烯[Cp_2Zr {eta（4）-Me_3SiC_4（SiMe_3）-C（C_2SiMe_3）= CSiMe_3}]（1）与腈（RC N，R = Me，Ph）的反应始于在金属-丁二炔键中插入氰化物基团，然后是炔-腈偶联，形成1-锆-2-氮杂环戊二烯-2，4-二烯。R = Me的反应产物通过二聚反应稳定，得到含有四元-N-Zr-N-Zr-环和两个相同的五元1-金属杂-2-氮杂环戊二烯环的化合物。在R = Ph的情况下，不能分离金属乳糖，并形成嘧啶。考察了该反应的催化潜力。对于PhN=C（H）Ph，在插入和偶联之后，再次建立了相应的1-锆-2-氮杂环戊-4-烯。该化合物与二氧化碳的反应导致环膨胀并形成七元产物，其在较高温度下释放CO2并返回反应物。通过核磁共振谱和单晶X-射线结构分析对上述产物进行了表征。
The reactions of the seven-membered zirconacyclocumulene [Cp2Zr{eta(4)-Me3SiC4(SiMe3)-C(C2SiMe3)=CSiMe3}] (1) with nitriles (RC N, R = Me, Ph) started with an insertion of a cyanide group into the metal-butadiyne bond followed by an alkyne-nitrile coupling and formation of 1-zircona-2-azacyclopenta-2,4-dienes. The reaction product for R = Me is stabilized by dimerization to give a compound containing a four-membered -N-Zr-N-Zr- ring and two identical five-membered 1-metalla-2-aza-cyclopentadiene rings. In case of R = Ph, a metallacycle could not be isolated, and a pyrimidine was formed. The catalytic potential of this reaction was investigated. For PhN=C(H) Ph, again after insertion and coupling, a corresponding 1-zircona-2-azacyclopenta-4-ene was established. The reaction of this compound with carbon dioxide led to ring expansion and formation of a seven-membered product, which released CO2 at higher temperature and to give back the reactant. The above-mentioned products were characterized by NMR spectroscopy and single-crystal X-ray structure analysis.