In the presence of 4Å MS, a mixture of terminal acetylene, cesium hydroxide and element selenium in DMF was stirred under N2 atomsphere at room temperature for 2 h, then alkyl bromides or diaryliodonium salts were added to the mixture and the resulting mixture was stirred at room temperature for 20 h to give acetylenic selenides in about 60% yields. The mechanism involved the reaction of terminal acetylene with cesium hydroxide to form the cesium alkynide, then selenium inserted into C—Cs bond and gave the cesium alkynylselenoate, which underwent nucleophilic substitution with alkyl bromides or diaryliodonium salts to give the corresponding acetylenic selenides.

Key words: cesium hydroxyl, diaryliodonium salt, alkyl halide, selenium, acetylenic selenide