Asymmetric synthesis of α-allyl-α-aryl α-amino acids by tandem alkylation/π-allylation of α-iminoesters

Org Lett. 2014 Apr 4;16(7):1948-51. doi: 10.1021/ol500506t. Epub 2014 Mar 25.

Abstract

The first asymmetric synthesis of α-allyl-α-aryl α-amino acids by means of a three-component coupling of α-iminoesters, Grignard reagents, and cinnamyl acetate is reported. Notably, the enolate from the tandem process provides a much higher level of reactivity and selectivity than the same enolate generated via direct deprotonation, presumably due to differences in the solvation/aggregation state. A novel method for removal of a homoallylic amine protecting group delivers the free amine congeners. The α-allyl group offers a means to generate further valuable α-amino acid structures as exemplified by ring closing metathesis to generate a higher ring homologue of α-aryl-proline.

Publication types

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

MeSH terms

  • Alkylation
  • Amino Acids / chemical synthesis*
  • Amino Acids / chemistry
  • Carboxylic Acids
  • Catalysis
  • Combinatorial Chemistry Techniques
  • Esters
  • Imines / chemistry*
  • Molecular Structure
  • Proline / analogs & derivatives*
  • Proline / chemical synthesis*
  • Proline / chemistry
  • Stereoisomerism

Substances

  • Amino Acids
  • Carboxylic Acids
  • Esters
  • Imines
  • Proline