A reactivity/affinity switch for parallel kinetic resolution: alpha-amino acid quasienantiomers and the resolution of cyclopropene carboxylic acids

J Am Chem Soc. 2004 Apr 14;126(14):4490-1. doi: 10.1021/ja049779t.

Abstract

A new type of parallel kinetic resolution (PKR) is reported in which quasienantiomers with very similar reactivities give products whose chromatographic properties diverge upon the addition of fluoride. This concept of a reactivity/affinity switch is applied to the PKR of cyclopropene carboxylic acids with all-carbon quaternary centers. This is the first application of alpha-amino acid quasienantiomers in PKR, and it is a complementary approach for acyltransfer systems where the asymmetry is induced by the nucleophile rather than the leaving group. Excellent diastereoselectivities (ranging from 90:10 to 99.5:5) and good yields were obtained for both quasienantiomeric products, and the reactions can be run on significant scale because the separation is trivial. High-level DFT calculations (B3LYP functional with the 6-31+G(d,p) basis set) provided transition-state structures with relative energies that are in accord with the experimental observations.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acids / chemical synthesis
  • Amino Acids / chemistry*
  • Carboxylic Acids / chemical synthesis
  • Carboxylic Acids / chemistry*
  • Cyclopropanes / chemical synthesis
  • Cyclopropanes / chemistry*
  • Kinetics
  • Stereoisomerism
  • Thermodynamics

Substances

  • Amino Acids
  • Carboxylic Acids
  • Cyclopropanes
  • cyclopropene