The preparation of new functionalized [2.2]paracyclophane derivatives with <i>N</i>-containing functional groups
作者:Henning Hopf、Swaminathan Vijay Narayanan、Peter G Jones
DOI:10.3762/bjoc.11.50
日期:——
The two isomeric bis(isocyanates) 4,12- and 4,16-di-isocyanato[2.2]paracyclophane, 16 and 28, have been prepared from their corresponding diacids by simple routes. The two isomers are versatile intermediates for the preparation of various cyclophanes bearing substituents with nitrogen-containing functional groups, e.g., the pseudo-ortho diamine 8, the bis secondary amine 23, and the crownophanes 18
Synthesis of planar chiral [2.2]paracyclophane-based bisoxazoline ligands bearing no central chirality and application to Cu-catalyzed asymmetric O–H insertion reaction
作者:Shinji Kitagaki、Kenta Sugisaka、Chisato Mukai
DOI:10.1039/c5ob00452g
日期:——
C2-symmetric planar chiral [2.2]paracyclophane-based bisoxazoline ligands effectively control the asymmetric induction during the Cu-catalyzed O–H insertion reaction of α-diazo esters.
Racemic 4,12-difunctionalized [2.2]paracyclophanes were synthesized and successfully resolved by (recycling) HPLC on a stationary CHIRALPAK IA phase at a semipreparative scale. Their absoluteconfigurations were determined by X-ray crystal structure analysis and/or by comparison of their specific optical rotations with literature data. These are valuable functionalized C2-symmetric building blocks
外消旋 4,12-双官能化 [2.2] 对环芳烃合成并通过(循环)HPLC 在半制备规模的固定 CHIRALPAK IA 相上成功解析。它们的绝对构型是通过 X 射线晶体结构分析和/或通过将它们的特定旋光度与文献数据进行比较来确定的。这些是有价值的功能化 C2 对称构件,用于形成更复杂的 V 形手性分子结构,正如一些探索性转化所证明的那样。
Thermotropic Liquid Crystals from Planar Chiral Compounds: [2.2]Paracyclophane as a Mesogen Core
作者:Valeria I. Rozenberg、Elena L. Popova、Henning Hopf
New thermotropic mesomorphic compounds containing a [2.2]paracyclophane (PC) unit were synthesized and investigated (Scheme). Carboxylic acids were selected as the starting PC building blocks. The influence of structural features on the stability of the mesomorphic phases was studied (Figs. 1 and 2): for this purpose. the structures of the PC-carboxylate unit and the organic fragment of the aryl-ester moiety were varied systematically. Esters derived from PC-monocarboxylic acid did not exhibit liquid-crystalline (LC) properties, while diaryl PC-dicarboxylates favored mesomorphism. Dicarboxylate substituents arranged in the paraposition provided LC phases in a broad temperature range and considerably increased the mesomorphic interval in comparison with that of the structurally related pseudo-para PC derivatives.