Synthesis of beta-substituted alpha-amino acids via Lewis acid promoted radical conjugate additions to alpha,beta-unsaturated alpha-nitro esters and amides

Org Lett. 2004 Feb 5;6(3):449-52. doi: 10.1021/ol036461h.

Abstract

[reaction: see text] Beta-substituted alpha,beta-unsaturated alpha-nitro esters and amides undergo radical conjugate additions when treated with an appropriate Lewis acid. Deuterium studies revealed that the acidic alpha-stereocenter of the alpha-nitro ester products does not racemize under strictly controlled workup conditions. The alpha-nitro amides did racemize significantly during chromatography, but this could be greatly minimized by subjecting the crude adducts to subsequent transformations. The conjugate addition products can be elaborated into beta-substituted alpha-amino acids in two simple steps.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acids / chemistry
  • Amides / chemistry*
  • Amino Acids / chemical synthesis*
  • Amino Acids / chemistry*
  • Esters / chemistry*
  • Free Radicals / chemistry
  • Magnetic Resonance Spectroscopy
  • Molecular Structure
  • Nitrates / chemistry*

Substances

  • Acids
  • Amides
  • Amino Acids
  • Esters
  • Free Radicals
  • Nitrates