Amberlyst-15: an efficient and reusable catalyst for the Friedel-Crafts reactions of activated arenes and heteroarenes with α-amido sulfones

The heterogeneous Amberlyst-15 catalyst displays efficient catalytic properties for the Friedel-Crafts reactions between an activated arenes or heteroarenes and α-amido sulfones. Various α-amido sulfones on treatment with 1,2,4-trimethoxy benzene give the Friedel-Crafts reaction products in very good yield. The reactions with heteroarenes show moderate yield of the product. The catalyst can be easily recycled without significant loss of activity.     

TiCl4-promoted intramolecular cyclization of 4-methoxy-5-arylethyl-1,3-dioxolan-2-ones: an expedient method to prepare 2-tetralones

DABCO is a very effective catalyst in the formation of 4-methoxy-5-arylethyl-1,3-dioxolan-2-ones 12 from the corresponding α-carbonatoaldehyde. Intramolecular cyclization of cyclic carbonates 12 promoted by TiCl₄ affords 2-tetralones 13 containing a variety of substituents in high yields.     

Lanthanide bis(trifluoromethanesulfonyl)amides, synthesis, characterization and catalytic activity

The synthesis of lanthanum, neodymium and ytterbium bis(trifluoromethanesulfonyl)amides, named triflimidates, from acetates, carbonates and oxides is investigated. When the synthesis is performed in water, all the salts contain one molecule of water and the lanthanum and neodymium salts synthesized from the acetates also contain one molecule of acetic acid. After removal of the water and acetic acid in refluxing ethanol, the salts are obtained anhydrous but associated for lanthanum and neodymium, whereas the ytterbium salt is monomeric and volatile. When the synthesis is performed directly in ethanol, the neodymium salt contains two molecules of coordinated ethanol.In non-hazardous solvents, these triflimidates are better catalysts than the analogous triflates toward either Friedel-Crafts acylations, or Fries transpositions or Baeyer-Villiger oxidations. Unexpectedly, the cerium(IV) triflimidate catalyzes the oxidation of aromatic ketones to give the corresponding acids.     

Chiral Pd-catalyzed enantioselective Friedel-Crafts reaction of indoles with γ,δ-unsaturated β-keto phosphonates

The catalytic enantioselective Friedel-Crafts alkylation reaction promoted by chiral palladium complexes is described. The treatment of indoles with γ,δ-unsaturated β-keto phosphonates under the mild reaction conditions afforded the corresponding Friedel-Crafts alkylation adducts with excellent enantioselectivities (up to 99% ee).     

微波辅助的Friedel-Crafts反应

Friedel-Crafts反应是有机合成中最有用的反应之一,它的应用范围十分广泛.利用微波辅助进行的Friedel-Crafts反应在有机合成方法学和新化合物合成的研究中逐渐受到广泛重视.本文综述了近年来微波辅助的Friedel-Crafts反应的研究进展和这类反应在新化合物合成中的应用.     

离子液体中12-苯甲酰基脱氢松香酸甲酯的合成

以离子液体[bmim]Br/AlCl3作为绿色反应介质,通过脱氢松香酸甲酯芳环上的Friedel-Crafts酰基化反应,合成了12-苯甲酰基脱氢松香酸甲酯,最佳合成条件为:脱氧松香酸甲酯、[bmim]Br、AlCl3、苯甲酰氯的摩尔比1:4:8:8,反应温度40℃,反应时间2h.用IR、MS、NMR和元素分析等方法对目标产物进行了分析和表征.结果表明,该合成方法具有反应条件温和、反应时间短及环境友好等优点.     

有机催化的不对称傅克烷基化反应

傅克烷基化反应是对芳香化合物衍生化的最为有效的方法之一, 而不对称傅克烷基化反应则提供了合成手性芳基衍生物的直接途径. 综述了近年来手性有机小分子催化的不对称傅克烷基化反应的研究进展.