We report the synthesis of a novel class of planar chiral bidentate aryl[2.2]paracyclophane ligands. For the first time in the [2.2]paracyclophanyl series the Pd-catalyzed Suzuki cross-coupling was employed for the formation of the arylparacyclophanyl skeleton. From the two possible approaches: (a) cross-coupling of [2.2]paracyalophanylboronic acids with aryl halides; (b) cross-coupling of [2.2]paracyclophanyl
Synthesis of novel planar-chiral [2.2]paracyclophane derivatives as potential ligands for asymmetric catalysis
作者:Michael Kreis、Martin Nieger、Stefan Bräse
DOI:10.1016/j.jorganchem.2005.10.031
日期:2006.5
The synthesis of a variety of new 4,5-disubstituted [2.2]paracyclophane derivatives has been achieved employing different cross-coupling reactions. By this methodology, a heteroatom-variation of successful catalyst ligands was achieved, giving rise to a modular ligand system. The X-ray structure of 4-hydroxy-5-(1′-hydroxy-1′-phenylethyl)-[2.2]paracyclophane was determined to elucidate the configuration
The First Examples of Planar Chiral Organic Benzimidazole Derivatives
作者:Gareth Rowlands、Peter Hitchcock、Andrew Hodgson
DOI:10.1055/s-2006-950432
日期:2006.9
The synthesis of a number of novel planar chiral benzimidazoles from [2.2]paracyclophane is reported. The key steps include a Buchwald-Hartwig amination of a sterically demanding triflate and the functionalisation of the C-2 bromide.
Development of a New Dimeric Cyclophane Ligand: Application to Enhanced Diastereo- and Enantioselectivity in the Catalytic Synthesis of β-Lactams
作者:Harald Wack、Stefan France、Ahmed M. Hafez、William J. Drury、Anthony Weatherwax、Thomas Lectka
DOI:10.1021/jo049804d
日期:2004.6.1
We detail the synthesis of a new C2-symmetric bis(cyclophane) ligand system that can be thought of as electronically analogous to binol, but which possesses the added “third dimension” of cyclophane chirality. The ligand synthesis involves a spontaneous (but unexpected) atropisomerization to the desired product. We have employed this ligand to form a metal complex that is an effective cocatalyst for
Efficient Synthesis of Enantiomerically and Diastereomerically Pure [2.2]Paracyclophane-Based N,O-Ligands
作者:Valeria I. Rozenberg、Tat’yana I. Danilova、Elena V. Sergeeva、Ivan. A. Shouklov、Zoya A. Starikova、Henning Hopf、Klaus Kühlein
DOI:10.1002/ejoc.200390076
日期:2003.2
syntheses of different enantiomerically and diastereomericallypure N,O-ligands with alkylamino and phenol groups attached to the [2.2]paracyclophane framework are described. Several transformations of the ortho-lithiated [2.2]paracyclophan-4-yl diethylcarbamate 7 and the reduction of the [2.2]paracyclophane imino derivatives 3, 4, 17, 18, and 21 allow the preparation of a wide range of compounds in which