Toolbox approach to the search for effective ligands for catalytic asymmetric Cr-mediated coupling reactions

J Am Chem Soc. 2009 Oct 28;131(42):15387-93. doi: 10.1021/ja905843e.

Abstract

Chromium catalysts derived from chiral sulfonamides represented by A effect the couplings of aldehydes with vinyl, allyl, or alkyl halides. With three distinct sites for structural modification, A affords access to a structurally diverse pool of chiral sulfonamides. The Cr catalysts derived from these sulfonamides exhibit a broad range of catalyst-substrate matching profiles. A strategy is presented to search for a satisfactory chiral sulfonamide for a given substrate. In order to demonstrate the generality and effectiveness of this approach, five diverse C-C bond-forming cases have been selected from the halichondrin synthesis. For each of the cases, two ligands have been deliberately searched for, to induce the formation of (R)- and (S)-alcohols, respectively, at the arbitrarily chosen efficiency level of ">or=80% yield with >or=20:1 stereoselectivity in the presence of <or=20 mol % of a Cr catalyst". For 9 out of the 10 cases studied, a satisfactory catalyst has been found within this pool of sulfonamides. Even for the remaining case, a Cr catalyst inducing stereoselectivity up to 8:1 has been identified.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Chromium / chemistry*
  • Ligands
  • Models, Molecular
  • Molecular Structure
  • Stereoisomerism
  • Sulfonamides / chemistry

Substances

  • Ligands
  • Sulfonamides
  • Chromium