铁粉促进断裂Se-Se键及其应用于合成α-芳硒基羰基化合物

Iron-Mediated Cleavage of Se—Se Bond for the Synthesis of α-Arylseleno Carbonyl Compounds

在铁粉存在下,以商用N,N-二甲基甲酰胺(DMF)作溶剂,90℃、氮气保护下,二芳基二硒醚与α-溴代羰基化合物反应,得到一系列α-芳硒基羰基化合物.考察了温度、时间、溶剂及铁粉用量对反应的影响,其中,温度对反应的影响最为明显.α-溴代羰基化合物中羰基上取代基对反应有很大影响,取代基为苯基时,转化率较甲基或烷氧基时低.反应机理可能是铁插入Se—Se键中形成亲核性Se Fe Se,随后与亲电底物α-溴代羰基化合物发生亲核取代.本方法使用铁粉促进断裂Se—Se键具有原料安全无毒、廉价易得、实验操作简便等优点.

In the presence of iron dust, using commercial N,N-dimethylformamide（DMF） as solvent, diaryl diselenides reacted with α-bromo carbonyl compounds at 90 ℃ under nitrogen atmosphere to afford a series of α-arylseleno carbonyl compounds. The influence of temperature, reaction time, solvent and iron dosage on the reaction was investigated. The results showed that the influence of temperature on the reaction was most obvious. In addition, the influence of carbonyl substituent in α-bromo carbonyl compounds was also more obvious. When carbonyl substituent is phenyl, the yield was lower than that of methyl or alkoxy. A proposal mechanism is that iron dust reacted with diaryl diselenides to give the nucleophilic species Ar Se Fe Se Ar, and nucleophilic species Ar Se Fe Se Ar and electrophilic α-bromo carbonyl compounds occured nucleophilic substitution reaction to obtain the desire products. The method using the iron dust to promote the cleavage of Se—Se bond has advantages of safe non-toxic, cheap and easy to get raw materials, simple procedure.