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.
Resolution of (±)-[2.2]paracyclophane-4,12-dicarboxylic acid
作者:Biao Jiang、Xiao-Long Zhao、Xiang-Ya Xu
DOI:10.1016/j.tetasy.2005.01.016
日期:2005.3
The resolution of (±)-[2.2]paracyclophane-4,12-dicarboxylic acid (±)-1 has been realized through the diastereomeric esters of (1S)-hydroxymethyl-4,7,7-trimethyl-2-oxabicyclo-[2.2.1]heptan-3-one, simply separated by flash chromatography and hydrolyzed with tBuOK/H2O. (R)-(−)-1 and (S)-(+)-1 were obtained in high enantiomeric excesses (>97%) while the determinations of the absolute configurations of
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.
Planar Chiral [2.2]Paracyclophane-Based Bisoxazoline Ligands and Their Applications in Cu-Mediated N–H Insertion Reaction
作者:Daniel M. Knoll、Yuling Hu、Zahid Hassan、Martin Nieger、Stefan Bräse
DOI:10.3390/molecules24224122
日期:——
New catalysts for important C–N bond formation are highly sought after. In this work, we demonstrate the synthesis and viability of a new class of planar chiral [2.2]paracyclophane-based bisoxazoline (BOX) ligands for the copper-catalyzed N–H insertion of α-diazocarbonyls into anilines. The reaction features a wide substrate scope and moderate to excellent yields, and delivers the valuable products