title: Stereocontrolled semi-syntheses of deguelin and tephrosin.
abstract: We describe stereocontrolled semi-syntheses of deguelin and tephrosin, anti-cancer rotenoids isolated from Tephrosia vogelii. Firstly, we present a new two-step transformation of rotenone into rot-2'-enonic acid via a zinc-mediated ring opening of rotenone hydrobromide. Secondly, following conversion of rot-2'-enonic acid into deguelin, a chromium-mediated hydroxylation provides tephrosin as a single diastereoisomer. An Étard-like reaction mechanism is proposed to account for the stereochemical outcome. Our syntheses of deguelin and tephrosin are operationally simple, scalable and high yielding, offering considerable advantages over previous methods.
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK. spring@ch.cam.ac.uk.
authors.forename: David A
authors.initials: DA
authors.lastname: Russell
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK. spring@ch.cam.ac.uk.
authors.forename: Julien J
authors.initials: JJ
authors.lastname: Freudenreich
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK. spring@ch.cam.ac.uk.
authors.forename: Joe J
authors.initials: JJ
authors.lastname: Ciardiello
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK. spring@ch.cam.ac.uk.
authors.forename: Hannah F
authors.initials: HF
authors.lastname: Sore
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK. spring@ch.cam.ac.uk.
authors.forename: David R
authors.identifier: http://orcid.org/0000-0001-7355-2824
authors.initials: DR
authors.lastname: Spring
mesh_terms: D008968:Molecular Conformation; D012402:Rotenone / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D012402:Rotenone; C480848:tephrosin; C107676:deguelin