Stereocontrolled Semisyntheses of Elliptone and 12aβ-Hydroxyelliptone
David A Russell1, Winston J S Fong1, David G Twigg1
1Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, U.K.
Abstract:
Operationally simple, stereocontrolled semisyntheses of the anticancer rotenoids elliptone and 12aβ-hydroxyelliptone, isolated from Derris elliptica and Derris trifoliata, respectively, are described. Inspired by the work of Singhal, elliptone was prepared from rotenone via a dihydroxylation-oxidative cleavage, chemoselective Baeyer-Villiger oxidation, and acid-catalyzed elimination sequence. Elaboration of elliptone to 12aβ-hydroxyelliptone was achieved via a diastereoselective chromium-mediated Étard-like hydroxylation. The semisynthesis of elliptone constitutes an improvement over previous methods in terms of safety, scalability, and yield, while the first synthesis of 12aβ-hydroxyelliptone is also described.
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