79409-49-7Relevant academic research and scientific papers
Iridoids, XXI. - Synthesis of Secologanin
Tietze, Lutz F.,Henke, Stephan,Remberg, Gerd
, p. 1413 - 1427 (2007/10/02)
Acid-catalyzed reaction of natural secologanin (1) with ethylene glycol to 5a, followed by acetylation gave the peracetylated acetal 5b in almost quantitative yield.Oxidation of 5b with equimolar or catalytic amounts of osmium tetraoxide afforded stereoselectively the diol 6 as main product (31percent resp. 28percent) besides recovered starting material. 5b was cleaved with lead tetraacetate to give 96percent of the aldehyde 10.Reaction of 10 with triphenylphosphonio-methanide led to the labelled secologanin derivative -5b and the pyran 12 in a 27percent and 52percent yield, respectively.Acid-catalyzed transacetalization of -5b to -5c, base-catalyzed solvolysis of the acetate groups to -5d and subsequent acid-catalyzed cleavage of the acetal gave secologanin (-1).To determine its configuration at C-9, 6 was transformed via 8a to the tricyclic system 8d, which was independently synthesized via a photocycloaddition of the galactose derivative 13 and diformylacetate 14.
