- Total Synthesis of Longeracinphyllin A
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The first and asymmetric total synthesis of longeracinphyllin A, a hexacyclic Daphniphyllum alkaloid, has been accomplished. A tetracyclic intermediate was prepared through silver-catalyzed alkyne cyclization and Luche radical cyclization. A phosphine-promoted [3 + 2] cycloaddition reaction was exploited to construct the sterically congested E ring bearing vicinal tertiary and quaternary centers. The cyclopentenone motif was assembled by using intramolecular Horner-Wadsworth-Emmons olefination. Raney Ni reduction delivered the tertiary amine from a thioamide precursor at a late stage.
- Li, Jian,Zhang, Wenhao,Zhang, Fei,Chen, Yu,Li, Ang
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supporting information
p. 14893 - 14896
(2017/10/31)
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- Enantioconvergent access to the enantiomerically pure building blocks (+)-or (-)-4-hydroxy-3-methyl-2-cyclohexenone using a chemoenzymatic process
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A convenient chemoenzymatic enantioconvergent access to enantiomerically pure (+)- or (-)-4-hydroxy-3-methyl-2-cyclohexenone is described using a one-pot two-step kinetic resolution-stereoinversion protocol followed by hydrolysis. The key step of the sequ
- Palombo, Elie,Audran, Gérard,Monti, Honoré
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p. 403 - 406
(2007/10/03)
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- Straightforward enantioselective synthesis of both enantiomers of karahana lactone using a domino ring-closure sequence
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A straightforward enantioselective synthesis of both enantiomers of karahana lactone is described starting from enantiopure (R) or (S)-4-hydroxy-3-methyl-cyclohex-2-en-1-one. The key step of the sequence is an acid-induced domino reaction with three pathways running. Because of the first description of karahana lactone as a solid, the structure was secured by X-ray structural analysis. (C) 2000 Elsevier Science Ltd.
- Galano, Jean-Marie,Audran, Gérard,Monti, Honoré
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p. 7477 - 7481
(2007/10/03)
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- Concise total syntheses of the sesquiterpenoids (-)-homalomenol A and (-)-homalomenol B
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The conjugate additions of the organocopper(I) reagents 22 and 27 to the enantiomerically homogeneous bicyclic enone 4 provided, after epimerization (NaOMe, MeOH) of the resultant product mixtures and appropriate chromatographic separations, the bicyclo[4.3.0]nonan-2-ones 24 and 28. Compounds 24 and 28 were readily converted, via two synthetic steps in each case, into the sesquiterpenoids (-)-homalomenols B (2) and A (1), respectively.
- Piers, Edward,Oballa, Renata M.
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p. 8439 - 8447
(2007/10/03)
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- Synthesis of optically active cyclohexenol derivatives via enzyme catalyzed ester hydrolysis of 4-acetoxy-3-methyl-2-cyclohexenone
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The optically active cyclohexenol derivatives 9a-9d, and 10a-10c are synthesized from (-)-6, which is obtained by enzymatic ester hydrolysis of racemic 8. Attempts towards the synthesis of the taxane skeleton are described.
- Polla, Magnus,Frejd, Torbjoern
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p. 5883 - 5894
(2007/10/02)
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