- Structures of Some New Sesquiterpenoid Metabolites of Marasmius alliaceus
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The sesquiterpenoids, alliacolide II (alliacol A)(2), 12-hydroxydehydroalliacolide (alliacol B) (3), 12-noralliacolide (5), 11- and 12-hydroxyalliacolide (6) and (7), respectively, and alliacolide (8) have been isolated from Marasmius alliaceus and their structures established by a combination of their spectra and chemistry.
- Farrell, Iain W.,Halsall, Thomas G.,Thaller, Victor,Bradshaw, A. Peter W.,Hanson, James R.
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- A Stereoselective Total Synthesis of (+/-)-Alliacol A and Congeners of Marasmius Alliaceus
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Synthesis of alliacolide (1), alliacol A (2), and 12-noralliacolide (4), members of the alliacane family of sesquiterpene lactones, was accomplished through both syn- and anti-modes of intramolecular SN' displacement.Two routes to 12-noralliacolide (4) are presented, which contrast brevity and efficiency in stereoselection (i.e. 14 -> 16/17 versus 37a/b -> 38).Since both routes culminate in C-ring annulation, introduction of the correct stereochemical arrangement relied heavily on the structural features of the hydrindane (AB) precursor(s).Choice of the proper AB system 24 facilitated production of tetrahydrofuran 38.With the full skeleton in place, 38 was efficiently epoxidized and oxidized to 4. 12-Noralliacolide (4) served as an appropriate relay substrate for conversion to alliacol A (2) and several other alliacanes.
- Clair, James J. La,Landsbury, Peter T.,Zhi, Ben-xin,Hoogsteen, Karst
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p. 4822 - 4833
(2007/10/02)
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- TOTAL SYNTHESIS OF (+/-)-12-NORALLIACOLIDE, (+/-)-ALLIACOL A AND (+/-)-ALLIACOLIDE
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The title compounds were prepared via a "one-pot" γ-lactone annulation sequence in which dilithium acetate functions as a bis-nucleophile, first at carbonyl and then at hindered allylic sulfonate centers (SN' orientation).
- Lansbury, Peter T.,Zhi, Ben-xin
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p. 5735 - 5738
(2007/10/02)
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