title: Total synthesis of chloptosin: a dimeric cyclohexapeptide.
abstract: Here we describe in full our investigations into the synthesis of the dimeric cyclohexapeptide chloptosin in 17 linear steps. Particularly, this work features an organocatalytic tandem process for the synthesis of the embedded piperazic acids, in which a differentially protected azodicarboxylate is used together with pyrrolidinyl tetrazole as the catalyst. The central biaryl bond is being formed by Stille coupling of two sterically demanding ortho-chloropyrroloindole fragments. The inherent flexibility of the synthetic strategy proved beneficial as the route could be adjusted smoothly during the progression of the synthesis programme.
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Oelke
authors.forename: Francesca
authors.initials: F
authors.lastname: Antonietti
authors.forename: Leonardo
authors.initials: L
authors.lastname: Bertone
authors.forename: Philippa B
authors.initials: PB
authors.lastname: Cranwell
authors.forename: David J
authors.initials: DJ
authors.lastname: France
authors.forename: Rebecca J M
authors.initials: RJ
authors.lastname: Goss
authors.forename: Tatjana
authors.initials: T
authors.lastname: Hofmann
authors.forename: Stephan
authors.initials: S
authors.lastname: Knauer
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Moss
authors.forename: Paul C
authors.initials: PC
authors.lastname: Skelton
authors.forename: Richard M
authors.initials: RM
authors.lastname: Turner
authors.forename: Georg
authors.initials: G
authors.lastname: Wuitschik
authors.forename: Steven V
authors.initials: SV
authors.lastname: Ley
mesh_terms: D002384:Catalysis; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry; D011724:Pyridazines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D010456:Peptides, Cyclic; D011724:Pyridazines; C414086:chloptosin