Enantioselective Total Synthesis of (–)-Siphonodictyal B and (+)-8-epi-Siphonodictyal B with Phosphatidylinositol 3-Kinase α (PI3Kα) Inhibitory Activity
The biologically interesting marine meroterpenoids (–)-siphonodictyal B and (+)-8-epi-siphonodictyal B were efficiently synthesized in 29–40 % overall yield in a longest linear sequence of 11 steps, starting from commercially available (+)-sclareolide. The synthesis involved the following crucial steps: (i) stereodivergent hydrogenation of a homoallylic decalin alcohol to install the requisite C8 stereogenic centre present in the decalin fragments; (ii) coupling of the decalin fragments with an aromatic moiety to assemble the desired carbon skeletons; and (iii) deprotection from multiple O-protective groups on the aromatic ring to complete the project synthesis. Both (–)-siphonodictyal B and (+)-8-epi-siphonodictyal B showed PI3Kα inhibitory activity, with potencies comparable to that of liphagal, a naturally occurring PI3Kα inhibitor. New structure–activity relationships for this class of marine meroterpenoids were also revealed.
Biogenetically inspired total synthesis of (+)-liphagal: A potent and selective phosphoinositide 3-kinase α (PI3Kα) inhibitor from the marine sponge Aka coralliphaga
A biologically attractive and structurally unique marine natural product, (+)-liphagal, was biomimetically synthesized in 29% overall yield in a longest linear sequence of 13 steps from commercially available (+)-sclareolide. This synthesis involved the following crucial steps: (i) stereocontrolled hydrogenation of an endo-olefinic decalin to install the C8 stereogenic centre present in the requisite decalin segment; (ii) coupling of the decalin segment with an aromatic moiety to assemble the desired carbon skeleton; (iii) ring expansion of a proposed biogenetic intermediate followed by benzofuran formation to establish the requisite tetracyclic core structure. A few new aspects of the proposed biosynthetic pathway to this class of natural products were revealed. Copyright
Synthesis of the Sesquiterpenes Albicanol, Drimanol, and Drimanic Acid, and the Marine Sesquiterpene Hydroquinone Deoxyspongiaquinol
A TiIII-mediated radical cyclization cascade has been used for the synthesis of the sesquiterpenes (+)-albicanol, (+)-drimanol, and (+)-drimanic acid. Starting from all-trans-farnesol, (+)-albicanol could be prepared in seven steps in an overal
G?hl, Matthias,Seifert, Karlheinz
p. 6975 - 6982
(2016/02/19)
ALTERNATIVE AND STEREOSELECTIVE SYNTHESIS OF 8β(H)-DRIMANE, A BICYCLIC SESQUITERPANE OF WIDESPREAD OCCURRENCE IN PETROLEUMS
Starting from drimenol, an alternative and stereoselective synthesis of 8β(H)-drimane, a widespread occurring sesquiterpane in petroleums, is described.The epimer 8α(H)-drimane was also prepared and a comparative 13C NMR spectral analysis of both stereoisomers was carried out.
Gonzales-Sierra, Manuel,Laborde, Maria de los Angeles,Ruveda, Edmundo A.
p. 431 - 442
(2007/10/02)
Fungal Metabolites. Part 5. Uvidins, New Drimane Sesquiterpenes from Lactarius uvidus Fries
Uvidin A (IIa) and uvidin B (IIc) along with (-)-drimenol have been isolated from Lactarius uvidus Fries (Basidiomycetes).The structure and the stereochemistry of the two uvidins have been determined both by spectroscopic data and chemical reactions.Compound (IIa) has been correlated with (+)-drimanol (VIII) by transformations into (VI) and then (VII).Reactions and spectroscopic data are discussed.
Bernardi, Maria De,Mellerio, Giorgio,Vidari, Giovanni,Vita-Finzi, Paola,Fronza, Giovanni