Structural Features of Lithio[3]ferrocenophane Systems Bearing Stabilizing Dimethylamino Substituents
Structural Features of Lithio[3]ferrocenophane Systems Bearing Stabilizing Dimethylamino Substituents
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DOI：
10.1021/om8001894
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发表时间：
2008-05
期刊：
影响因子：
2.8
通讯作者：
Chao Chen;R. Fröhlich;G. Kehr;G. Erker
中科院分区：
文献类型：
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作者：
Chao Chen;R. Fröhlich;G. Kehr;G. Erker
α-二甲氨基[3]二茂铁衍生物3与正丁基锂反应，在二茂铁单元的相邻CP环上发生定向o-金属化反应，选择性地生成(R*，R*，p-S*)非对映异构体4。同样，锂化制得(R*，p-S*)-13。这两种化合物都在晶体中形成中介型二聚体，具有中心的C2Li2四元环部分。化合物13与过量的正丁基锂反应生成(13·n-BuLi)二聚体，并用X-射线衍射法进行了表征。X-射线晶体结构分析表明，非桥二茂铁衍生物1-(二甲氨基苯基)二茂铁(16)与叔丁基锂的定向锂化合成(R*，p-R*)-17具有相反的立体选择性，在固体中形成手性二聚体结构。
Treatment of the α-dimethylamino[3]ferrocenophane derivative 3 with n-butyllithium results in a directed o-metalation at the adjacent Cp ring of the ferrocene unit to selectively yield the (R*,R*,p-S*) diastereomer 4. Similarly, lithiation of rac-12 gives (R*,p-S*)-13. Both these compounds form meso-type dimers in the crystal that feature a central C2Li2 four-membered-ring moiety. Compound 13 crystallizes with excess n-butyllithium to form a (13·n-BuLi) dimer that was also characterized by X-ray diffraction. Directed lithiation of the nonbridged ferrocene derivative 1-(dimethylaminobenzyl)ferrocene (16) with tert-butyllithium resulted in an opposite stereoselectivity to yield (R*,p-R*)-17, which forms a chiral dimeric structure in the solid state, as was revealed by its X-ray crystal structure analysis.