在催化剂氢氧化铯存在下,DMF 做溶剂,室温、空气氛围中亚磷酸二乙酯与炔硒醚不是发生预期的加成反应,而是还原断裂Se-CsP键,得到相应的端炔和磷酸硒酯,收率89%~95%。考察了与炔及硒相连的取代基对反应的影响,结果表明,取代基的电性对反应没有明显的影响。反应机理为氢氧化铯与亚磷酸二乙酯反应生成的(EtO)2 P-(O)Cs+亲核进攻炔硒醚中的Se生成磷酸硒酯和RC≡C-Cs+,RC≡C-Cs+随后水解得到 RC≡CH,同时形成催化剂氢氧化铯。本方法为断裂Se-CsP提供了一条新的简便且有效的路径。
In the presence of cesium hydroxide,the reaction of O,O-diethylphosphonate with alky-nylselenides at room temperature does not provide the expected additional product by using dimethyl for-mamide (DMF)as the solvent,but rather causes the cleavage of Se-Csp bond and gives the corresponding terminal alkynes and Se-aryl phosphoroselenoates in 89~95% yields.The influence of substituent at the alkynes and selenium atom on the reaction was investigated,and the results showed that the reaction was not sensitive to the electronic nature.The reaction mechanism was that O,O-diethylphosphonate reacted with cesium hydroxide to produce (EtO)2 P-(O)Cs+,which underwent nucleophilic attacks on alkynylse-lenides to produce Se-aryl phosphoroselenoates and RC≡C-Cs+.The latter was hydrolyzed in the presence of water to form terminal alkynes and catalyst cesium hydroxide.The method could provide a new and sim-ple path for the cleavage of Se-CsP.