Enantioselective synthesis of beta2-amino acids via Rh-catalyzed asymmetric hydrogenation with BoPhoz-type ligands: important influence of an N-H proton in the ligand on the enantioselectivity

J Org Chem. 2008 Mar 7;73(5):2015-7. doi: 10.1021/jo702510m. Epub 2008 Jan 30.

Abstract

A series of BoPhoz-type ligands were successfully applied in the rhodium-catalyzed asymmetric hydrogenation of a number of beta-substituted or unsubstituted alpha-(phthalimidomethyl)acrylates, affording good to excellent enantioselectivities. The results suggested that the presence of an N-H proton in the BoPhoz backbone could significantly improve the enantioselectivity, and ligand (Sc,Rp)-1d, bearing two CF3-groups in the 3,5-position of the phenyl ring of aminophosphino moiety, showed the highest enantioselectivity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / chemical synthesis*
  • Amino Acids / chemistry
  • Ligands
  • Magnetic Resonance Spectroscopy
  • Organophosphonates / chemistry*
  • Rhodium / chemistry*
  • Spectrometry, Mass, Electrospray Ionization
  • Stereoisomerism

Substances

  • Amino Acids
  • Ligands
  • Organophosphonates
  • Rhodium