脂肪族化合物的亲核三氟甲基化

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   在化合物中引入三氟甲基的另一类方法就是通过CF3-的亲核反应实现,主要包括两大类:CuCF3对卤代烃的亲核取代和TMSCF3对羰基化合物的亲核取代。


CuCF3试剂

三氟甲基铜试剂是向有机分子引入三氟甲基的一种重要合成子,它通常是现场产生的。在这里我们主要讨论应用于脂肪族化合物的三氟甲基酮试剂:FSO2CF2CO2Me/CuI。中科院上海有机所的陈庆云在研究中发现FSO2CF2CO2Me是一个很好的二氟卡宾前体1,当在催化量的CuI存在下,FSO2CF2CO2Me在DMF中加热至60~80 oC可产生CF3Cu,生成的CF3Cu可与卤化物进行三氟甲基化反应2。

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A solution of FSO2CF2CO2CH3 (1.80 mL,14.15 mmol) in DMF (3.6 ml) was added dropwise over a period of 2 h to a mixture of STM.(3.34 mmol), CuI (1.60 g, 8.39 mmol) and HMPA (1.5 mL) in DMF(9.0 mL) at 75 oC. The reaction mixture was stirred at 75 oC for 10 h before being cooled to room temperature. Saturated aq. NH4Cl(10 mL) was added and the mixture was extracted with Et2O (3×5 mL). The organic layer was washed with water, brine and dried over Na2SO4. The solvent was removed in vacuo. Purification of the residue by column chromatography on silica gel gave the desired product.

【参考文献】

1. Chen, Q. Y.; Zhu, S. Z. ScienticSinica B. 1987, 30, 561.

2. Chen, Q. Y.; Wu, S. W. J.Chem. Soc. Chem. Commun. 1989, 705-706.

3. Zhang, X.; Qing, F. L.; Yang, Y. G.; Yu, J.; Fu,X. K. Tetrahedron Lett. 2000, 41,   2953-2955.


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