150662-02-5Relevant academic research and scientific papers
Access to Atropisomerically En-riched Biaryls by the Coupling of Aryllithiums with Arynes under Control by Homochiral Oxazolines
Yalcouye, Boubacar,Berthelot-Bréhier, Ana?s,Augros, David,Panossian, Armen,Choppin, Sabine,Chessé, Matthieu,Colobert, Fran?oise,Leroux, Frédéric R.
, p. 725 - 732 (2016)
We report the preparation of axially stereoenriched biphenyls by the coupling of in situ generated aryllithiums and arynes using chiral oxazoline auxiliaries. The design of the aryne precursors, the choice of oxazoline and the reaction conditions were key to accessing the desired, highly substituted, atropisomerically enriched biarylic products. In one case, the two atropo-diastereomers could be obtained in isomerically pure form by column chromatographic separation and their absolute configurations established by X-ray crystallography. The stereoselectivity of the reaction seems to be governed by subtle parameters.
A rapid total synthesis of an ellagitannin
Nelson,Meyers
, p. 2577 - 2580 (2007/10/02)
The ellagitannins are galloyl esters of glucose that contain at least one chiral biaryl (digalloyl) subunit. Included in this family are the tellimagrandins (1-3). The first asymmetric synthesis of (S)-4,4',5,5',6,6'-hexamethoxy-2,2'-diphenic acid, a ubiquitous subunit in ellagitannins, is reported by utilization of an intermolecular oxazoline-mediated asymmetric Ullmann coupling. Attachment of this acid to an appropriate glucose core resulted in the synthesis of an ellagitannin.
