【硝化反应】硝基烷烃类化合物的制备 / 开普饭

烷烃硝化反应

与芳烃类化合物相比，在常规硝化剂的作用下，饱和脂肪烃类化合物的硝化反应很难发生。金刚烷选择性的N-或O-官能团化也已见诸报道。在-78 °C 臭氧条件下，二氧化氮有选择性地与金刚烷的桥头位置发生反应，得到硝基化产物¹

To a stirred mixture of hydrocarbon 1 (0.27 g, 2.0mmol) and dichloromethane (30 mL) was added liquid nitrogen dioxide (2.0 mL, 60mmol) at -78 °C and then ozonized oxygen was bubbled through at a low flow rate. After 0.5 h, the reaction was quenched with aq. NaHCO₃. The organic phase was separated, washed and dried with Na₂SO₄. Removal of the solvent under reduced pressure left a white solid residue which was chromatographed on deactivated alumina using hexane-ethyl acetate as eluentto give the pure nitro derivative 2 (0.32 g, 90%), mp 162-163 ^oC.

对于一些易得的甲基硅烷类或烯丙基锡烷类化合物，通过硝基去甲基硅烷化²或硝基去锡烷化³，可以比较有效的获得一些硝基烷烃。

In a 50 mL three-necked flask was added 1 mmol of allyltrimethylsilane to 10 mL of dry dichloromethane. The system was cooled to -78 ^oC. NO₂⁺BF₄^- (1mmol, 1.33 g) was slowly added during a period of 20 min. A slow stream of dry nitrogen was passed through the system to purge trimethylfluorosilane and borontrifluoride formed in the reaction. After 30 min all the nitronium salt had disappeared. The mixture was then allowed to warm to room temperature, dichloromethane distilled off at atmospheric pressure, and the product distilled under vacuum: bp 62 ^oC/(25 mm); yield, 80%.²

Treatment of allyl trimethylstannane with 1.0 equiv of C(NO₂)₄ in DMSO at 17 ^oC leads to isolation of the corresponding allyl nitro in 56% yield.²⁵

饱和烃类在自由基催化剂：N-羟基邻苯二甲酰亚胺（NHPI）催化作用下，可以通过烷基自由基的生成进而得到相应的硝基化合物⁴。

NO₂ was used as a liquid at 0 ^oC. To a pearshaped flask (100 mL) were added NHPI (98 mg, 0.6 mmol) and cyclohexane (5mL). The flask was closed with a glass stopper and weighed. Then NO₂(0.75 mL) was quickly added using a Hamilton gas-tight syringe, and the flask was reclosed with the glass stopper. The flask was weighed again in order to measure the NO₂ added (115 mg, 2.5 mmol). The flask was cooled in an ice bath and then quickly attached to a condenser, and the mixture was stirred at 70 ^oC for 14 h. After the reaction, GC and GC-MS analyses were performed. The yields of the products were estimated from the peak areas based on the internal standard technique using GC. The products were isolated by column chromatography on silica gel with hexane/ethyl acetate (10/1 ± 3/1,v/v), and were identified by comparison of their analytical data with those of authentic samples.⁴

【硝化反应】硝基烷烃类化合物的制备

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