Selection between Diastereomeric Kinetic vs Thermodynamic Carbonyl Binding Modes Enables Enantioselective Iridium-Catalyzed anti-(α-Aryl)allylation of Aqueous Fluoral Hydrate and Difluoroacetaldehyde Ethyl Hemiacetal

J Am Chem Soc. 2018 Aug 1;140(30):9392-9395. doi: 10.1021/jacs.8b05725. Epub 2018 Jul 18.

Abstract

Enantioselectivity increases with increasing carbonyl electrophilicity in 2-propanol-mediated reductive couplings of aldehydes with branched aryl-substituted allylic acetates to form products of carbonyl anti-(α-aryl)allylation. This unusual phenomenon is caused by aldehyde coordination to diastereomeric kinetic vs thermodynamic carbonyl binding sites that deliver enantiomeric products. Exploiting this effect, anti-diastereo- and enantioselective (α-aryl)allylations of fluoral hydrate and difluoroacetaldehyde ethyl hemiacetal were developed.

Publication types

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

MeSH terms

  • 2-Propanol / chemistry
  • Acetaldehyde / analogs & derivatives*
  • Acetaldehyde / chemistry
  • Acetals / chemical synthesis*
  • Acetates / chemistry
  • Allyl Compounds / chemical synthesis*
  • Atropine Derivatives / chemical synthesis*
  • Catalysis
  • Iridium / chemistry*
  • Kinetics
  • Oxidation-Reduction
  • Stereoisomerism
  • Thermodynamics

Substances

  • Acetals
  • Acetates
  • Allyl Compounds
  • Atropine Derivatives
  • trifluoroacetaldehyde hydrate
  • Iridium
  • Acetaldehyde
  • 2-Propanol