Synthesis and assignment of absolute configuration of the iridoid 9-deoxygelsemide.
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.
D'Alfonso
Alessandro
A
Dipartimento di Chimica Organica, Università di Pavia, Via Taramelli 10, 27100 Pavia, Italy.
Pasi
Maurizio
M
Porta
Alessio
A
Zanoni
Giuseppe
G
Vidari
Giovanni
G
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
C547305:9-deoxygelsemide; D039823:Iridoids; D007783:Lactones