A new stereoselective synthesis of (E)-α-β-Unsaturated-γ-dicarbonyl compounds by the Henry reaction
A new stereoselective synthesis of (E)-α-β-Unsaturated-γ-dicarbonyl compounds by the Henry reaction
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DOI：
10.1021/jo00097a061
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发表时间：
1994-09
影响因子：
3.6
通讯作者：
R. Ballini;G. Bosica
中科院分区：
文献类型：
--
作者：
R. Ballini;G. Bosica
（E）-烯二酮类化合物是合成重要分子的重要中间体，如异莲心素、罗酮、2香料、3信息素、4大环化合物和其它天然产物。这些化合物的合成方法，特别是2-单取代或2，5-二取代呋喃的开环方法，已引起人们的极大关注。这种转化可以通过几种不同的氧化方法进行，48· 5-11但是这些方法具有某些缺点，例如在环裂解之前呋喃的区域选择性烷基化，使用潜在的爆炸性试剂，苛刻的反应条件，以及形成（E）-和（Z）-异构体的混合物或仅形成（Z）-异构体，其需要强酸来异构化为（E1）-化合物。因此，通过替代方法制备（E）-烯二酮体系是重要的。硝基烷烃在复杂的有机合成中被证明是有用的，因为硝基官能团的许多可能的转化，也许更重要的是因为在非常温和的条件下进行的各种碳-碳键形成反应。12-18硝基羟醛（亨利）19反应及其变体已广泛用于碳-碳键的形成。由于所需的条件温和，发现这种反应已广泛应用于许多重要分子的合成是不足为奇的。15· 18-30作为硝基羟醛反应的推广，（1）（a）弗洛伊德，. B。有机化学杂志，1978，43，1641。(b)Elliot，JD; Hetmanski，M.; Stoodley，JJ Chem. Soc. Perkin Trans.1 1981，1782. (2)Shono，T.; Matsumura，Y.; Hamaguchi，H.;中村，K化学快报。1976年1249年
(E)-Enediones are valuable intermediates for the syn-thesis ofimportant molecules such as prostaglandins,* 1 rethrolones, 2 perfumes, 3 pheromones, 4 macrocycles, 5 and other natural products. Considerable attention hasbeen paid to methods for the synthesis of these compounds, in particular the ring cleavage of 2-mono or 2, 5-disub-stituted furans. This transformation can be performed by several different oxidative methods, 48· 5-11 but these methods suffer from certain drawbacks, such as regiose-lective alkylation of the furan before the ring cleavage, the use of potentially explosive reagents, severe reaction conditions, and formation of mixtures of (E)-and (Z)-isomers or exclusive formation of the (Z)-isomer, which requires a strong acid for isomerization to the (El-compound. The preparation of the (E)-enedione system via alternative methods thus is important. Nitroalkanes have proved useful in complex organic syntheses because of the many possible transformations of the nitro functionality and perhaps more importantly because of the variety of carbon—carbon bond-forming reactions that proceed under very mild conditions. 12-18 The nitroaldol (Henry) 19 reaction and its variants have been used extensively in carbon—carbon bond forma-tion. 20 Because of the mild conditions required, it is not surprising to find that this reaction has been applied broadly in the synthesis of many important mole-cules. 15· 18-30 As an extension of the nitroaldol reaction,(1)(a) Floyd,. B. J. Org. Chem. 1978, 43, 1641.(b) Elliot, JD; Hetmanski, M.; Stoodley, JJ Chem. Soc. Perkin Trans. 1 1981, 1782.(2) Shono, T.; Matsumura, Y.; Hamaguchi, H.; Nakamura, K Chem. Lett. 1976, 1249.