549-84-8Relevant articles and documents
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Godtfredsen,Vangedal
, p. 1013,1016 (1957)
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Symmetry-driven synthesis of indole alkaloids: Asymmetric total synthesis of (+)-yohimbine, (-)-yohimbone, (-)-yohimbane, and (+)-alloyohimbane
Aube,Ghosh,Tanol
, p. 9009 - 9018 (2007/10/02)
Total asymmetric syntheses of the target alkaloids are reported. The syntheses involve the preparation of enantiomerically pure (S,S)-1,3,3a,4,7,7a-hexahydro-2(H)-inden-2-one 7 and its meso isomer 5. Each ketone is then converted into a ring-expanded lactam using an oxaziridine synthesis/rearrangement protocol. The applications of Bischler-Napieralski ring constructions along with appropriate functional group transformations afford enantiomerically enriched alloyohimbane or yohimbane from the meso-or C2-symmetric ketones, respectively. A cis-5,6-diacetoxy compound (18) derived from the (S,S)-ketone served as the starting material for the total syntheses of the more highly functionalized alkaloids. Accordingly, a site-specific insertion of the indole-containing side chain was accomplished via stereoselective formation of an oxaziridine followed by its stereospecific rearrangement. The selectivity of this sequence allowed for the differentiation of alcohols at C-17 and C-18 (yohimbine numbering) and the synthesis of Δ18,19-yohimbone. This α,β-unsaturated ketone was converted into either (-)-yohimbone or (+)-yohimbine using standard chemistry.
Synthesis of yohimbines. 5. Enantioselective total synthesis of yohimbine and β-yohimbine antipodes
Blasko,Knight,Honty,Szantay
, p. 655 - 663 (2007/10/02)
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