- Potential intermediate, (±)-di-o-acetyl-3α-phenylselanyl-3,3a-dihydro-B-nor-6,7a- secolycorin-5-one for synthesis of the Amaryllidaceae alkaloid lycorine: Formal and total syntheses of (±)-lycorine
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Formal and total syntheses of the Amaryllidaceae alkaloid, (±)-lycorine 1, were achieved by new synthetic routes via (±)-di-o-acetyl-3α-phenylselanyl-3,3a-dihydro-B-nor-6,7a- secolycorin-5-one 32. Namely, stereoselective intramolecular Diels-Alder reaction of triene ester 5 afforded, in good yield, the cis-lactone 6, which was converted into β(stereochemical)-hydroxy-γ-lactam 23. Oxidation of silyl ether 24 with m-chloroperbenzoic acid gave only β-(tert-butyldimethylsiloxy)-α-epoxide 25, the stereostructure of which was determined by its X-ray crystallographic analysis. Payne rearrangement of compound 25 and successive acetylation furnished α(stereochemical)-acetoxy-β(stereochemical)-epoxy γ-lactam 29, which was transformed into (±)-lycorine 1 by construction of the B ring. Formal total synthesis of (±)-lycorine 1 is also described.
- Hoshino, Osamu,Ishizaki, Miyuki,Kamei, Keisuke,Taguchi, Minoru,Nagao, Takashi,Iwaoka, Kiyoshi,Sawaki, Shohei,Umezawa, Bunsuke,Iitaka, Yoichi
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p. 571 - 580
(2007/10/03)
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- A New and Stereoselective Synthetic Route to an Amaryllidaceae Alkaloid, (+/-)-Lycorine
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Formal and total syntheses of an Amaryllidaceae alkaloid, (+/-)-lycorine, were achieved by a new synthetic route via (+/-)-3-(phenylseleno)-seco-dihydro-B-norlycorin-5-one.
- Hoshino, Osamu,Ishizaki, Miyuki,Kamei, Keisuke,Taguchi, Minoru,Nagao, Takashi,et al.
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p. 1365 - 1368
(2007/10/02)
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