Chiral Monodentate Oxazoline Ligand

  • Author: Li Grundl
  • Published: 08 March 2018
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
  • Source / Publisher: Journal of the American Chemical Society/ACS Publications
  • Associated Societies: American Chemical Society (ACS), USA
thumbnail image: Chiral Monodentate Oxazoline Ligand

The metal-catalyzed carbofunctionalization of activated alkenes has been studied extensively, but the corresponding transformation of unactivated alkenes is still rare. The Pd-catalyzed carbofunctionalization of unactivated alkenes can be realized by using an amide-linked aminoquinoline (AQ) directing group. However, the strong coordination of the N,N-bidentate AQ group makes the enantioselective reaction challenging. The desired ligand needs to bind the only available site on Pd and accelerate the enantiodetermining step to compete with the background nonasymmetric reaction.


Gong Chen, Nankai University and Collaborative Innovation Center of Chemical Science and Engineering, both Tianjin, China, and Pennsylvania State University, University Park, USA, Gang He, Nankai University and Collaborative Innovation Center of Chemical Science and Engineering, Qian Peng, Nankai University, and colleagues have developed a monodentate oxazoline ligand bearing an N-3,5-di-CF3-phenyl substituted indole (MOXin, pictured). It can be easily prepared in high yield in three steps from low-cost amino acid precursors.


The researchers achieved the first Pd-catalyzed enantioselective hydrocarbofunctionalization of AQ-containing 3-alkenamides with indoles, using Pd(OAc)2 as a catalyst and MOXin as a ligand in the presence of o-phenyl benzoic acid at 60 °C in MeOH. The products were obtained in good to excellent yields and enantioselectivities. The directing group AQ can be removed after the reaction without causing a racemization of the products.


 

Article Views: 1339

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

Bookmark and Share

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission. more


CONNECT:

ChemistryViews.org on Facebook

ChemistryViews.org on Twitter ChemistryViews.org on YouTube ChemistryViews.org on LinkedIn Sign up for our free newsletter


A product of ChemPubSoc Europe (16 European Chemical Societies)and Wiley-VCH