不稳定的磷叶立得和醛进行正常wittig反应给出z-烯烃为主的产物。schlosser发展了从非稳定化的叶立得出发,高选择的形成到e-烯烃的wittig反应改良法。

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反应机理


首先形成叶立得与锂盐络合物,而后在低温下与醛反应,形成加成产物3。此时再加入一当量强碱如苯基锂,然后用叔丁基醇质子化,可立体选择性的得到syn两性化合物5,最后升温发生β-syn消除得e-烯烃。



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反应实例

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参考文献


1. schlosser, m., christmann, k. f. angew. chem., int. ed. engl. 1966, 5, 126.

2. schlosser, m., christmann, k. f. liebigs ann. chem. 1967, 708, 1-35.

3. schlosser, m. top. stereochem. 1970, 5, 1-30.

4. maryanoff, b. e., reitz, a. b. phosphorus and sulfur and the related elements 1986, 27, 167-189.

5. sano, s., kobayashi, y., kondo, t., takebayashi, m., maruyama, s., fujita, t., nagao, y. tetrahedron lett. 1995, 36, 2097-2100.

6. duffield, j. j., pettit, g. r. j. nat. prod. 2001, 64, 472-479.

7. couladouros, e. a., mihou, a. p. tetrahedron lett. 1999, 40, 4861-4862.

8. khiar, n., singh, k., garcia, m., martin-lomas, m. tetrahedron lett. 1999, 40, 5779-5782.


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