title: Selective access to E- and Z-ΔIle-containing peptides via a stereospecific E2 dehydration and an O → N acyl transfer.
abstract: A concise synthesis of peptides that contain E- or Z-dehydroisoleucine (ΔIle) residues is reported. The key reaction is an unusual anti dehydration of β-tert-hydroxy amino acid derivatives that is mediated by the Martin sulfurane. A subsequent tandem Staudinger reduction-O → N acyl transfer process forges an amide bond to the ΔIle residue with minimal E/Z alkene isomerization. Density functional calculations attribute the stereospecific dehydration to a highly asynchronous E2 anti process.
authors.affiliation: Department of Chemistry and Biochemistry, Brigham Young University , Provo, Utah 84602, United States.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Ma
authors.forename: Jintao
authors.initials: J
authors.lastname: Jiang
authors.forename: Shi
authors.initials: S
authors.lastname: Luo
authors.forename: Yu
authors.initials: Y
authors.lastname: Cai
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Cardon
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Kay
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Ess
authors.forename: Steven L
authors.initials: SL
authors.lastname: Castle
mesh_terms: D000475:Alkenes / Q000737:chemistry; D000595:Amino Acid Sequence; D003681:Dehydration; D006860:Hydrogen Bonding; D007532:Isoleucine / Q000737:chemistry*; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D010455:Peptides; D007532:Isoleucine