title: Asymmetric synthesis of α-allyl-α-aryl α-amino acids by tandem alkylation/π-allylation of α-iminoesters.
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.
authors.affiliation: Department of Chemistry, Penn Merck High Throughput Experimentation Laboratory, University of Pennsylvania , Philadelphia, Pennsylvania 19104-6323, United States.
authors.forename: John M
authors.initials: JM
authors.lastname: Curto
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Dickstein
authors.forename: Simon
authors.initials: S
authors.lastname: Berritt
authors.forename: Marisa C
authors.initials: MC
authors.lastname: Kozlowski
mesh_terms: D000478:Alkylation; D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D002264:Carboxylic Acids; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D004952:Esters; D007097:Imines / Q000737:chemistry*; D015394:Molecular Structure; D011392:Proline / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D002264:Carboxylic Acids; D004952:Esters; D007097:Imines; D011392:Proline