The Research On The Synthesis Of 1-Iodoalkynes, Ethers And Diselelides By The Catalysts Of Cesium Ions

1-Iodoalkynes are one of the useful intermediates in organic synthesis. For example they are widely used in coupling reactions. By far the methods of synthesis 1-iodoalkynes however exist somewhat disadvantages, such as long reaction time, expensive reagents, harsh reaction conditions, hard to handle and so on. Our research purpose is to design a method that the reagents are cheap, the reactions are in mild conditions, and the work-up is simple. Cesium hydroxide is an inorganic superior base, it can react with weak acids to form the corresponding stable Carbon or hetero anions, which are very strong nucleophiles. They can react smoothly with many reagents at room temperature. So we decide to make terminal alkynes react with iodines by using CsOH as base. The results showed that the employment of CsOH in the presence of TBAI and 4 ? MS makes the iodination of terminal alkynes come true in the solvent of THF. In a short time with good to excellent yields proved this method is a good protocol to form 1-iodoalkynes. However the iodination of terminal alkynes needs equivalent amount of CsOH. Its price limits its further application. Regarding to its economic factor, we design using KOH (2.0eq)/ Cs2CO3(0.2eq) system to take place of quantitative CsOH to develop the iodination of terminal alkynes. The experiments results showed that the employment of KOH (2.0eq)/ Cs2CO3 (0.2eq) system involving the use of TBAI and 4 ? MS in DMF can also make the iodination smoothly accomplished, only need a little longer reaction time. The results of this protocol would promise the 1-iodoalkynes for further application.On the research of ethers synthesis, we use CsCl instead of Cs2CO3 as catalyst for the synthesis of alkyl phenyl ethers. We found at room temperature, taking DMF as solvent, the KOH (2.0eq)/ CsCl(0.2eq) system can make phenols react with both reactive and unreactive primary halide in a one-pot way, with excellent yields of corresponding alkyl phenyl ethers.Further more, we take the KOH (2.0eq)/ CsCl(0.2eq) system for the O-alkylation of alcohols for the alkyl ethers synthesis. This protocol involves the use of TBAI, 4 ? MS in DMF. The experiments result satisfied us: Various substrates including unreactive primary and tertiary alcohols were converted smoothly to the corresponding ethers at room temperature, both the reactive and unreactive primary halides are proper electrophiles.The ethers of diselenides are an important intermediates in organic synthesis. Many methods have been reported in literature. Among them, the tolsylates react with dipotasium(or disodium) disenilide need a high temperature of 100℃. However for those unstable substrates at high temperature are unfit in this system. By the employment of a catalytic amount of cesium carbonate, we found that the tolsylates can smoothly react with dipotasium disenelide at room temperature, with good to excellent yields of corresponding dialkyl disenilides.