A convergent asymmetric synthesis of γ-butenolides
摘要:
The addition of aldehydes to the new enantiomerically pure lithiated sulfoxide-orthoester 13 yielded gamma -butenolides of high enantiomeric purities after elimination of phenylsulfinic acid. The cyclocondensation with ketones was less stereoselective. This new asymmetric synthesis of gamma -butenolides has been applied to a convergent preparation of the antifungal antibiotic (+)-cerulenin. (C) 2001 Elsevier Science Ltd. All rights reserved.
Four newsigmatropicsequences triggered by the regiocontrolled [2,3]-Wittig rearrangement of unsymmetrical bis-allylic ethers (1) to the l,5-dien-3-ols (2) arc described, which provide unique, regiocontrolled methods for the synthesis of a wide variety of unsaturatedcarbonylcompounds possessing interesting molecular frameworks. The newly developed sequences include the [2,3]-Wittig-Claisen, the
A Concise Synthesis of (+)-Cerulenin from a Chiral Oxiranyllithium
作者:Neelakandha S. Mani、Craig A. Townsend
DOI:10.1021/jo9618177
日期:1997.2.1
(+)-Cerulenin, a potent fungal inactivator of fatty acid synthases, has been prepared in optically pure form by a sequence involving reaction of a chiral oxiranyllithium with (4E,7E)-nonadienal. Synthesis of the former takes advantage of a particularly favorable Sharpless epoxidation and metalation to a configurationally stable organolithium, while the latter is available in quantity by a direct and improved route.
SEQUENTIAL [2,3]WITTIG AND CLAISEN REARRANGEMENT: A FACILE SYNTHETIC METHOD FOR (<i>E</i>,<i>E</i>)-4,7-ALKADIENALS AND -ALKADIENOIC ACIDS. A NEW FORMAL SYNTHESIS OF (±)-CERULENIN
作者:Koichi Mikami、Naoyuki Kishi、Takeshi Nakai
DOI:10.1246/cl.1981.1721
日期:1981.12.5
The regioselective [2,3]Wittig rearrangement of bis-allylic ethers followed by the Claisen rearragement permits ready access to (E,E)-4,7-alkadienals and -alkadienoic acids. The versatility of the sigmatropic sequence is demonstrated within the context of a new formal synthesis of (±)-cerulenin possessing an interesting spectrum of biological activities.