4269-05-0Relevant 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 (2017/01/18)
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.
Atropo-diastereoselective coupling of aryllithiums and arynes — variations around the chiral auxiliary
Augros, David,Yalcouye, Boubacar,Berthelot-Bréhier, Ana?s,Chessé, Matthieu,Choppin, Sabine,Panossian, Armen,Leroux, Frédéric R.
, p. 5208 - 5220 (2016/08/02)
The atropo-selective coupling of in situ generated arynes and aryllithiums bearing various chiral auxiliaries ortho to lithium (tert-butylsulfoxide, para-tolylsulfoxide, tartrate-derived chiral diethers and oxazolines) is described. Chiral oxazolines showed the best results in terms of yields of coupling products. Different reaction parameters like the nature of the aryne precursor, the oxazoline, the alkyllithium base or the solvent revealed to be crucial for obtaining good yields and for diastereoselection.
