- Enantioselective creation of quaternary carbon centers through addition-elimination reaction: Asymmetric nitroolefination of 3-substituted 2-oxindoles
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Nitroolefination of 3-substituted 2-oxindoIes with nitroenamine (5) afforded the corresponding products having quaternary carbon centers with high ee in good yield. Application of this method to concise syntheses of (-)-esermethole (24) and (-)-pseudophrynaminol (28) is described.
- Fuji, Kaoru,Kawabata, Takeo,Ohmori, Toshiumi,Shang, Muhong,Node, Manabu
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p. 951 - 964
(2007/10/03)
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- An efficient asymmetric synthesis of nitroolefinic lactones with chiral nitroenamines possessing bulky chiral leaving groups
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An efficient asymmetric nitroolefination of enolates 4a-c, 5 afforded multifunctional group nitroolefinic lactones 7a-e and 8a,b containing stereogenic quaternary carbon centers using bulky chiral nitroenamines 1a,b-3a,b as chiral auxiliaries. Studies on the effect of the bulkiness of leaving group showed that bulky nitroenamines la,b gave higher ees and yields than those of the less bulky 2a,b-3a,b. A possible cyclic transition model is proposed to elucidate the S selectivity.
- Yang, Xiaowu,Wang, Rui
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p. 3275 - 3281
(2007/10/03)
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