Jump to main content
Jump to site search

Issue 33, 2017
Previous Article Next Article

Transfer hydrogenation of ortho-hydroxybenzophenone ketimines catalysed by BINOL-derived phosphoric acid occurs by a 14-membered bifunctional transition structure

Author affiliations

Abstract

Chiral BINOL-derived phosphoric acids catalyse the transfer hydrogenation of ketimines using Hantszch esters. In many cases the nitrogen on the imine binds to the catalyst through the catalyst hydroxyl group and the nucleophile forms a second hydrogen bond to the phosphoryl oxygen. DFT and ONIOM calculations show that the introduction of an ortho-hydroxyaryl group on the carbon atom of the ketimine leads the reaction to proceed through a 14-membered bifunctional mechanism. The transition states of these reactions involve both hydrogen bonding from the hydroxyl group on the imine and the nucleophile's proton to the phosphate catalyst. This mechanistic pathway is lower in energy than the conventional route, consistent with the experimentally observed increased rates of reaction relative to imines that are not derived from ortho-hydroxybenzophenone. To complement the high-level calculations, an accessible qualitative model has been developed that predicts the correct sense of stereoinduction for all examples.

Graphical abstract: Transfer hydrogenation of ortho-hydroxybenzophenone ketimines catalysed by BINOL-derived phosphoric acid occurs by a 14-membered bifunctional transition structure

Back to tab navigation

Supplementary files

Publication details

The article was received on 02 Jun 2017, accepted on 28 Jul 2017 and first published on 28 Jul 2017


Article type: Paper
DOI: 10.1039/C7OB01345K
Citation: Org. Biomol. Chem., 2017,15, 6943-6947
  • Open access: Creative Commons BY license
  •   Request permissions

    Transfer hydrogenation of ortho-hydroxybenzophenone ketimines catalysed by BINOL-derived phosphoric acid occurs by a 14-membered bifunctional transition structure

    J. P. Reid and J. M. Goodman, Org. Biomol. Chem., 2017, 15, 6943
    DOI: 10.1039/C7OB01345K

    This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Material from this article can be used in other publications provided that the correct acknowledgement is given with the reproduced material.

    Reproduced material should be attributed as follows:

    • For reproduction of material from NJC:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the Centre National de la Recherche Scientifique (CNRS) and the RSC.
    • For reproduction of material from PCCP:
      [Original citation] - Published by the PCCP Owner Societies.
    • For reproduction of material from PPS:
      [Original citation] - Published by The Royal Society of Chemistry (RSC) on behalf of the European Society for Photobiology, the European Photochemistry Association, and RSC.
    • For reproduction of material from all other RSC journals:
      [Original citation] - Published by The Royal Society of Chemistry.

    Information about reproducing material from RSC articles with different licences is available on our Permission Requests page.

Search articles by author

Spotlight

Advertisements