【炔烴合成】corey-fuchs反應(官能團轉化)構建中間炔烴

炔類化合物是有機合成中的重要中間體，目前已經發展出了一些非常常用的人名反應，例如Corey-Fuchs reaction, Seyferth-Gilbert reaction和 Sonogashira Coupling reaction。合成炔類化合物的方法按照反應類型可以分為兩大類：官能團轉化構建碳碳三鍵；在分子中引入帶有碳碳三鍵的部分。但是在反合成設計上，按照炔基在分子中所處的位置（處於末端；或中間位置）對合成方法進行分類，更加方便應用，因此，接下來介紹的是中間炔烴的合成。

corey-fuchs反應(官能團轉化)構建中間炔烴

與末端炔烴類似，使用corey-fuchs反應在第二步加入親電試劑捕獲炔負離子，即可得到中間炔烴。

實例

To a mixture of Ph3P (1.45 g, 5.51 mmol) and Zn dust (0.36 g, 5.51 mmol) in CH2Cl2 (20 mL) was added to CBr4 (1.83 g, 5.51 mmol) at 0 oC. The resultant yellow slurry was stirred at 0 oC for 15min, and 23 oC for 15 min. Compound A (1.14 g, 2.755 mmol) in CH2Cl2 (8 mL) was added via cannula. The reaction mixture was stirred at 23 oC for 6h. Pentane (100 mL) was added and the precipitates formed were filtered off through Celite. The solid residue was dissolved in CH2Cl2(10 mL), reprecipitated with pentane (30 mL), and filtered again. This process was repeated a total of three times. The combined pentane filtrates were concentrated and the resulting liquid was purified on silica gel (1% ethylacetate/hexanes) to give (3E,5R,6R,7E,9S)-1,1-dibromo-3,5,7,9-tetramethyl-6-(t-butyldimethylsilyloxy)-11-phenyl-1,3,7-undecatriene (1.54 g, 98 %) as a colorless oil. (3E,5R,6R,7E,9S)-1,1-dibromo-3,5,7,9-tetramethyl-6-(t-butyldimethylsilyloxy)-11-phenyl-1,3,7-undecatriene (6.90 g, 13.0 mmol) in THF (65 mL) cooled to-78 oC was added nBuLi (17.2 mL, 2.5 M in hexanes, 42.9 mmol) in 5 min. The resulting yellow solution was stirred for 15 min. at -78 oC then warmed to 0 oC and stirred for 30 min. at 0 oC. The reaction mixture was then cooled back to -78 oC and MeI (4.0 mL, 65 mmol) was added. The reaction mixture was gradually warmed to 23 oC over 12 h, quenched with satd. NH4Cl, filtered through Celite, extracted with ether, dried over MgSO4, and concentrated. Flash chromatography (silica gel, 1% ethyl acetate/hexanes) gavep roduct (5.00 g, 100%) as a clear oil.

Reference: Org. lett.2004, 3245-3248.

相關連結：

【炔烴合成】親核取代合成端炔

【炔烴合成】Sonogashira Coupling/De-TMS reaction反應

【炔烴合成】從末端烯烴或者末端雙滷代物構建末端炔烴

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