An efficient Darzens reaction promoted by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)
作者:Juan Luo、Lanfang Hu、Minghao Zhang、Qiang Tang
DOI:10.1016/j.tetlet.2019.06.034
日期:2019.7
efficient DBU promoted Darzens reaction utilising α-haloketones containing an enolizable α′-hydrogen is reported. This method diastereoselectively afforded the corresponding α,β-epoxyketones good to excellent yields in an one-pot reaction without using any transition metals or additives. Furthermore, haloketones without an α′-hydrogen are also applicable in this reaction.
Synthesis of β-oxo carbonyl and thiocarbonyl compounds via basic sulfur abstraction
作者:Saúl Silva、Christopher D. Maycock
DOI:10.1016/j.tet.2019.130552
日期:2019.10
suitable thioesters represents a mild method for the formation of carbon-carbon bonds and the formation of 1,3-dicarbonyl compounds. A study of the scope and limitations of this reaction for the synthesis of these or mixed 1,3-carbonyl/thiocarbonyl compounds by a base promoted sulfur abstraction rearrangement is described. These reactions were typically very clean and the products were obtained in good
A novel reaction of α-haloketone (α-bromo and α-chloro ketone) with irradiation under microwave gave the corresponding α-hydroxyketone and pyrazine derivative in good yields. In the case of α,α′-dibromo ketone, α-diketone was obtained. This reaction affords a new, clean and convenient synthetic method for α-hydroxyketone, α-diketone, α-chloro ketone and pyrazine derivative.
Halogenation of Carbonyl Compounds by an Ionic Liquid, [AcMIm]X, and Ceric Ammonium Nitrate (CAN)
作者:Brindaban C. Ranu、Laksmikanta Adak、Subhash Banerjee
DOI:10.1071/ch07061
日期:——
An ionic liquid, acetylmethylimidazolium halide ([AcMIm]X), in combination with ceric ammoniumnitrate promotes halogenations of a wide variety of ketones and 1,3-keto esters at the α-position. The ionic liquid acts here as reagent as well as reaction medium, and thus the reaction does not require any organic solvent or conventional halogenating agent. The reaction is completely arrested when the radical
离子液体乙酰甲基咪唑鎓卤化物 ([AcMIm]X) 与硝酸铈铵结合可促进多种酮和 1,3-酮酯在 α 位的卤化。离子液体在此既充当试剂又充当反应介质,因此该反应不需要任何有机溶剂或常规卤化剂。当使用自由基猝灭剂 TEMPO 时,反应完全停止。还提出了一种似是而非的激进机制。