- A+
α位含有亚甲基硫醚基团的环烷酮和二甲基亚甲基锍(dimethylsulfonium methylide)反应得到环氧化合物,接着在加热条件(或硅胶催化)下重排得到五元环硫代缩醛,在碘(或硫酸汞)催化下脱硫芳香化得到呋喃。
反应操作
Furan (5). Ketone 2 (9 g, 16.1 mmol) in ether was added at -78 ℃with stirring to a suspension of ylide prepared by treating Me3S+I-(10.1 g, 48.3 mmol) in 1 L Et2O at -10 ℃ with 24.2 mL of 2 MNaHMDS in THF (3 equiv). The mixture was kept for 6 h at -60 ℃, then at 0 ℃, hexane and water were added and the aq layer was extracted with hexanes. The hexane layers were washed and worked
up as usual to yield epoxide 3. After the latter was heated for 2 h in 400 mL PhMe at 90 ℃, I2 (406 mg, 0.1 equiv) in toluene was added at 20 ℃. After 15 min, evaporation and chromatography (hexanes to
2% Et2O-hexanes) gave 5.1 g (70%) of 5.
【Kishi Y, Tet Lett., 1998, 39, 8929】
相关文献
1 Garst ME, Spencer TA J Am Chem Soc 1973 95 250
2 Garst ME, Spencer TA J Org Chem 1983 48 2442
3 Wong HNC J Org Chem 1994 59 3917
4 Kishi Y Tet Lett 1998 39 8929
5 Katritzky AR ARKIVOC 2004 ii 109
6 Kishi Y J Synth Org Chem Jpn 2004 1205
编译自:Organic Syntheses Based On Name Reactions, 3RdEd, A. Hassner, Page 176-177.
相关反应
1962年,E.J. Corey和M. Chaykovsky发现利用钠氢对三甲基卤化锍(trimethylsulfoxonium halides)脱质子可以得到一种活性化合物,二甲基亚砜亚甲基叶立德【dimethylsulfoxonium methylide (I),Corey叶立德】。简单的醛酮与其反应可以得到环氧化合物。与此类似二甲基亚甲基鋶叶立德【dimethylsulfoniummethylide (II)】也可以和醛酮反应得到环氧化合物。
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