BINAP(O) Induces Enantioselectivity

  • ChemPubSoc Europe Logo
  • Author: Lois O'Leary
  • Published Date: 31 December 2012
  • Source / Publisher: ChemCatChem/Wiley-VCH
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
thumbnail image: BINAP(O) Induces Enantioselectivity

Related Societies

The Mizoroki-Heck reaction is widely used for the enantioselective synthesis of sterically strained molecules with tertiary or quaternary carbon centers. The chiral phosphine ligand 2,2,'-bis(diphenylphosphino)-1,1,'-binaphthyl (BINAP) has been the running favorite for this reaction. However, in desymmetrizing Mizoroki-Heck cyclizations, the use of BINAP yields nearly racemic material. For these reactions, Martin Oestreich and Thorsten H. Wöste, Technische Universität Berlin, Germany, have uncovered the enantioselectivity of BINAP(O) as a palladium ligand, which contains an oxidized phosphine center P=O.

BINAP(O) induced unprecedented enantiocontrol. Up to 18-fold increases in enantioselectivity with yields of up to 94 % were achieved for the cyclizations with BINAP(O) as a chiral ligand compared to those with the conventional BINAP ligand.

BINAP(O) acts as a hemilabile chiral ligand, allowing for reversible coordination of the weak donor P=O group. As a bidentate ligand, BINAP(O) mediates the equilibration of diastereomeric alkene-palladium(II) complexes. Its subsequent dissociation from the palladium(II) atom renders it monodentate, which is known to be advantageous to the ring-closing reaction. These results have great implications for the scope of enantioselective cyclization reactions, putting BINAP(O) on the map!


Article Views: 2971

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