Cesium Base Promoted Alkylation, Arylthiolation And Arylselenolation Of Diethyl Malonate, Ethyl Acetoacetate

β-Dicarbonyl compounds are one of the useful intermediates in organic synthesis. The structure of the active methylene generating carbanion in the presence of strong base, they can react with many electrophilic reagent.By far the methods of synthesisβ-dicarbonyl compounds derivatives however exist somewhat disadvantages, such as use not readily available reagents, have strict reaction conditions, hard to handle and so on. Reports pointed out that cesium base can optimize the reaction conditions, enhance the yield of reaction, caused for widespread interest. We studies the alkylation, arylthiolation and arylselenolation of diethyl malonate and ethyl acetoacetate. Main work and research results are as follows:(1).β-Dicarbonyl compounds alkylation reaction usually use sodium alkoxide as a strong base, But that requires strictly anhydrous operation and not enough security. We improved the alkylation ofβ-dicarbonyl compounds. We design in the presence of CsOH as base, using DMF as solvent, at ambient temperature, the diethyl malonate and ethyl acetoacetate with varieties of alkyl halides go give corresponding substituted product.When the reactions were carried out with 1 equivalents alkyl halides, giving about 60 % yield of monoalkylated product. In contrast, the dialkylated product (65% yield) was obtained when reactions were carried out with 2.2 equivalents alkyl halides.The method under mild reaction conditions, apply a wide range, easy operation. Compared to conventional techniques, It is a good methodology to prepare alkylatedβ-Dicarbonyl Compounds.(2). There are two currently known methods for arylthiolation or arylselenolation ofβ-dicarbonyl compounds.One method is transfor diaryl disulfides(diaryl diselenides) to arylsulfenyl bromide or arylselenenyl bromide, respectively.This process should use the toxic bromine. Another method is diaryl disulfides(diaryl diselenides) reaction withβ-dicarbonyl compounds directly. However, in method, only 50 percent of the S(Se) atomic participate in the reaction. To overcome these shortcomings, we design in the presence of CsOH as base and under an air atmosphere, diaryl disulfides(diaryl diselenides) react with diethyl malonate and ethyl acetoacetate to give the expected product in good yield. The reaction under mild conditions, raw materials easily obtained, does not require anhydrous conditions. The aryl sulfur (selenide) anions generated in the reaction oxided by air to re-formation disulfides(diaryl diselenides). This reaction take full advantage of sulfur(selenium) atom, is typically an economic atomic reaction. This provides for the C-S bonds, C-Se bonds formation of a new synthesis methods.