Fullerene Dendrimers and Lipofullerenes with an Inherently Chiral Hexaaddition Pattern
Fullerene Dendrimers and Lipofullerenes with an Inherently Chiral Hexaaddition Pattern
复制标题
DOI：
10.1002/(sici)1099-0690(200003)2000:6
复制
发表时间：
2000-03
影响因子：
2.8
通讯作者：
Françis Djojo;Elena Ravanelli;O. Vostrowsky;A. Hirsch
中科院分区：
文献类型：
--
作者：
Françis Djojo;Elena Ravanelli;O. Vostrowsky;A. Hirsch
描述了对映体纯的C3-对称富勒烯树枝状聚合物all-R-fA-7、all-S-fC-8、all-R-fC-9和all-S-fA-10以及涉及八面体[3：3]加成模式的脂富勒烯all-S-fA-11和all-S-fC-12的简易合成。以具有已知绝对构型的C3对称三[双（4-苯基-2-恶唑啉）亚甲基]富勒烯1、2、3和4为前体。八面体加成模式的完成是通过用树枝状3，5-二羟基苄基溴丙二酸酯5和亲脂性溴丙二酸双十八烷基酯6进行三次环丙烷化来实现的。前体三加合物的绝对构型保留在固有手性C3对称六加合物7-12中。所有六加成物7-12的结构和异构体纯度通过NMR光谱和其它技术明确地证明。用树枝状六元加合物all-S-fC 8和all-S-fA 10进行的初步实验表明，这些大分子配体对苯乙烯与重氮乙酸乙酯的立体选择性环丙烷化反应具有催化性能。
The facile synthesis of enantiomerically pure C3-symmetrical fullerene dendrimers all-R-fA-7, all-S-fC-8, all-R-fC-9, and all-S-fA-10, as well as lipofullerenes all-S-fA-11 and all-S-fC-12 involving an octahedral [3:3] addition pattern is described. The C3 symmetrical tris[bis(4-phenyl-2-oxazoline)methano]fullerenes 1, 2, 3, and 4 with known absolute configuration were used as precursors. The completion of the octahedral addition pattern was achieved by a threefold cyclopropanation with the dendritic 3,5-dihydroxybenzylic bromomalonate 5 and the lipophilic dioctadecyl bromomalonate 6. The absolute configurations of the precursor trisadducts were retained in the inherently chiral C3-symmetrical hexakisadducts 7-12. The structure and the isomeric purity of all hexakisadducts 7-12 were unambiguously proven by NMR spectroscopy and other techniques. Preliminary experiments with the dendritic hexakisadducts all-S-fC8 and all-S-fA10 revealed that these macromolecular ligands posess catalytic properties with respect to stereoselective cyclopropanations of styrene with ethyl diazoacetate.