Intramolecular Oxonium Ylide Formation鈥揫2,3] Sigmatropic Rearrangement of Diazocarbonyl-Substituted Cyclic Unsaturated Acetals: A Formal Synthesis of Hyperolactone C
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- 作者：David M. Hodgson ; Stanislav Man ; Kimberley J. Powell ; Ziga Perko ; Minxiang Zeng ; Elena Moreno-Clavijo ; Amber L. Thompson ; Michael D. Moore
- 刊名：Journal of Organic Chemistry
- 出版年：2014
- 出版时间：October 17, 2014
- 年：2014
- 卷：79
- 期：20
- 页码：9728-9734
- 全文大小：403K
- ISSN：1520-6904
文摘
Rh(II)-catalyzed oxonium ylide formation鈥揫2,3] sigmatropic rearrangement of 伪-diazo-尾-ketoesters possessing 纬-cyclic unsaturated acetal substitution, followed by acid-catalyzed elimination鈥搇actonization, provides a concise approach to 1,7-dioxaspiro[4.4]non-2-ene-4,6-diones. The process creates adjacent quaternary stereocenters with full control of the relative stereochemistry. An unsymmetrical monomethylated cyclic unsaturated acetal leads to hyperolactone C, where ylide formation鈥搑earrangement proceeds with high selectivity between subtly nonequivalent acetal oxygen atoms.