Catalytic, asymmetric, and stereodivergent synthesis of non-symmetric β,β-diaryl-α-amino acids

J Am Chem Soc. 2015 Jan 21;137(2):999-1006. doi: 10.1021/ja511872a. Epub 2015 Jan 7.

Abstract

We report a concise, enantio- and diastereoselective route to novel nonsymmetrically substituted N-protected β,β-diaryl-α-amino acids and esters, through the asymmetric hydrogenation of tetrasubstituted olefins, some of the most challenging examples in the field. Stereoselective generation of an E- or Z-enol tosylate, when combined with stereoretentive Suzuki-Miyaura cross-coupling and enantioselective hydrogenation catalyzed by (NBD)2RhBF4 and a Josiphos ligand, allows for full control over the two vicinal stereogenic centers. High yields and excellent enantioselectivities (up to 99% ee) were obtained for a variety of N-acetyl, N-methoxycarbonyl, and N-Boc β,β-diaryldehydroamino acids, containing a diverse and previously unreported series of heterocyclic and aryl substituted groups (24 examples) and allowing access to all four stereoisomers of these valuable building blocks.

MeSH terms

  • Amino Acids / chemical synthesis*
  • Amino Acids / chemistry*
  • Catalysis
  • Chemistry Techniques, Synthetic
  • Hydrogenation
  • Models, Molecular
  • Molecular Conformation
  • Stereoisomerism
  • Substrate Specificity

Substances

  • Amino Acids