Multiple Cyclopropanations of C70. Synthesis and characterization of bis-, tris-, and tetrakis-adducts and chiroptical properties of bis-adducts with chiral addends, including a recommendation for the configurational description of fullerene derivatives w
作者:Andreas Herrmann、Markus Rüttimann、Carlo Thilgen、François Diederich
DOI:10.1002/hlca.19950780705
日期:1995.11.1
chiroptical contributions from the chirally functionalized fullerene chromophores (Fig.7). Since the addition patterns on the fullerene surface in each pair of diastereoisomers have an enantiomeric relationship, their CD spectra closely resemble those expected for two enantiomers. In the third constitutional isomer 11, the addition pattern on the fullerene surface is C2v-symmetrical, and optical activity only
在系统研究中,研究了在以1,8-二氮杂双环[5.4.0] undec-7-ene(DBU)为碱的情况下,C 70与2-溴丙二酸酯的多个环丙烷化的区域选择性(Bingel反应)。在富勒烯的两个相反的极点上,由最金字塔形的sp 2 -C原子形成的66个键优先发生双加合物的形成,并且在与非手性双[(乙氧基羰基)甲基] 2-溴丙二酸酯(13a)的反应中产生三个组成上异构的双(甲基)富勒烯(方案2)。其中两个C 2-对称(±)-1和(±)-2,是手性的;以前的调查中未曾考虑过的事实。首次观察到第三C 2 v对称异构体3的形成。提出了富勒烯衍生物的构型描述,所述富勒烯衍生物由于特定的官能化模式而具有手性发色团。C 70与旋光性双[(S)-1-苯基丁基] 2-溴丙二酸双((S)-1-苯基丁基)(13b)的环丙烷化反应生成五个旋光性C 2对称双加合物7-11,可以通过制备型HPLC分离并进行充分表征(方案