Base-Stimulated 1,2-, 1,4-, and 1,6-Eliminations in Suitably Substituted Alkylidenesuccinates Leading to Natural and Unnatural Conjugated Alkenyl(methyl)maleic Anhydrides
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- 作者：Prashant S. Deore ; Narshinha P. Argade
- 刊名：Journal of Organic Chemistry
- 出版年：2014
- 出版时间：March 21, 2014
- 年：2014
- 卷：79
- 期：6
- 页码：2538-2546
- 全文大小：520K
- 年卷期：v.79,no.6(March 21, 2014)
- ISSN：1520-6904
文摘
With dimethyl maleate as the starting material, facile stereoselective syntheses of natural and unnatural conjugated alkenyl(methyl)maleic anhydrides have been described. The key reactions were base-endorsed novel 1,2-, 1,4-, and 1,6-eliminations in the corresponding alkylidenesuccinate derivatives. The 1,2-eliminations in cyclic carbonate and sulfite by regioselective abstraction of methine protons with the respective release of CO2 and SO2 provided a conjugated ketone product. The characteristic 1,4- and 1,6-elimination reactions with respective release of acetone and mesylate furnished the corresponding unsaturated alcohols. The obtained allylic alcohols were transformed into conjugated alkenyl(methyl)maleic anhydrides via oxidation followed by a Horner鈥揥adsworth鈥揈mmons reaction pathway in very good yields. The mechanistic aspects involved in these significant elimination reactions have also been described in brief.