Direct Catalytic Asymmetric Synthesis of Trifluoromethylated γ-Amino Esters/Lactones via Umpolung Strategy

J Org Chem. 2019 Jan 18;84(2):994-1005. doi: 10.1021/acs.joc.8b02893. Epub 2019 Jan 8.

Abstract

Enabled by the discovery of new cinchonium salts and coadditives, a direct and efficient asymmetric access to trifluoromethylated γ-amino esters/lactones has been realized through the enantioselective and diastereoselective umpolung reaction of trifluoromethyl imines with acrylates or α,β-unsaturated lactones as carbon electrophiles. At 0.5-5.0 mol % catalyst loadings, the newly developed catalytic system activates a variety of imine substrates as unconventional nucleophiles to mediate highly chemo-, regio-, diastereo-, and enantioselective C-C bond forming reactions. The developed synthetic protocol represents an excellent strategy to target a series of versatile and enantiomerically enriched γ-amino esters/lactones in good to excellent yields from the readily available starting materials. Additionally, we found that the epi-vinyl catalysts based on cinchonidine and quinine promote a similarly high enantioselective reaction generating the opposite configuration of chiral products in a highly efficient manner, which allows convenient access to either the R- or S-enantiomer of the chiral amine products in high yields and excellent enantioselectivities.

Publication types

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

MeSH terms

  • Acetaldehyde / analogs & derivatives*
  • Acetaldehyde / chemistry
  • Amino Acids / chemical synthesis*
  • Amino Acids / chemistry
  • Catalysis
  • Esters / chemical synthesis*
  • Esters / chemistry
  • Imines / chemistry
  • Lactones / chemical synthesis*
  • Lactones / chemistry
  • Molecular Structure
  • Quinidine / chemistry*
  • Stereoisomerism

Substances

  • Amino Acids
  • Esters
  • Imines
  • Lactones
  • trifluoroacetaldehyde hydrate
  • Acetaldehyde
  • Quinidine