Highly effective and regioselective Michael addition of indoles to α,β-unsaturated ketones promoted by pentafluorophenylammonium triflate
作者:Samad Khaksar、Seyed Mohammad Vahdat、Fatemeh Rezaee
DOI:10.1016/j.crci.2012.08.002
日期:2013.2
Abstract A simple, inexpensive, environmentally friendly and efficient route for Michaeladdition of indoles to α,β-unsaturated ketones using pentafluorophenylammonium triflate (PFPAT) as a catalyst is described. Various indole derivatives were synthesized in good to excellent yields. The preparation of PFPAT catalyst from simple and readily available starting materials makes this method more affordable
The inexpensive Br2 can serve as a novel Lewis acid catalyst for Friedel–Crafts alkylation of indoles with α,β-unsaturatedketones. Under the catalysis of only 3 mol % of Br2, this Michael addition proceeded smoothly with high efficiency and broad substrate scope. Moreover, theoretical calculations suggested that Br2 possesses only the modest power to activate chalcones and is inferior to most tested
Efficient Friedel–Crafts alkylation of indoles and pyrrole with enones and nitroalkene in water
作者:Najmedin Azizi、Fezzeh Arynasab、Mohammad R. Saidi
DOI:10.1039/b610263h
日期:——
An operationally simple and entirely green protocol for heteropoly acid (10 mg) catalyst conjugate addition of indoles and pyrrole to unsaturated carbonyl compounds and nitroalkene in water at ambient temperature in good to excellent yields has been developed.
The C3-selective Friedel-Crafts alkylation of indoles with electron-deficient olefins has been achieved using a mesoporous aluminosilicate catalyst with 3D cage-type porous structure to furnish the 3-alkylindole derivatives in excellent yields due to its high surface area, large pore volume and high acidity. Pyrrole also reacted efficiently under similar reaction conditions to give the corresponding 2-alkylated pyrrole derivatives in good yields.
Abstract A simple and novel bimetallic catalyst, an iron and magnesium complex (Fe‐Mg‐hexamethylphosphoramide (HMPA)), with dual activation was found to be an effective and promising catalyst for the Michael‐type Friedel–Craftsreactions of indoles with chalcones. This novel catalytic system has the advantages of highly efficient, mild reaction conditions and exhibits high reactivity and selectivity
摘要 一种简单而新颖的双金属催化剂,铁和镁配合物(Fe-Mg-六甲基磷酰胺(HMPA)),具有双重活化作用,被发现是吲哚与查耳酮的 Michael 型 Friedel-Crafts 反应的有效且有前景的催化剂。这种新型催化体系具有高效、反应条件温和、反应活性和选择性高的优点,使其成为合成吲哚衍生物的有用且有吸引力的方法。