title: Synthesis and assignment of absolute configuration of the iridoid 9-deoxygelsemide.
abstract: The first enantioselective synthesis of 9-deoxygelsemide, belonging to a rare group of iridoids isolated from Gelsemium plants, is described. The key synthetic steps are a variant of the Woodward-Prevost reaction to install the characteristic cis-alpha-1,2-dioxygenated system at C-6 and C-7 with complete diastereoselectivity. Construction of the dihydropyran ring was achieved via formylation of lactone I, followed by dehydration of the corresponding lactol. The synthesis allowed assignment of absolute configuration to 9-deoxygelsemide and related iridoids.
authors.affiliation: Dipartimento di Chimica Organica, Università di Pavia, Via Taramelli 10, 27100 Pavia, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: D'Alfonso
authors.forename: Maurizio
authors.initials: M
authors.lastname: Pasi
authors.forename: Alessio
authors.initials: A
authors.lastname: Porta
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zanoni
authors.forename: Giovanni
authors.initials: G
authors.lastname: Vidari
mesh_terms: D031450:Gelsemium / Q000737:chemistry; D039823:Iridoids / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D007783:Lactones / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: C547305:9-deoxygelsemide; D039823:Iridoids; D007783:Lactones