RUTHENIUM PORPHYRIN CATALYZED FRIEDEL–CRAFTS TYPE REACTION OF ARENES WITH IMINES
摘要:
Cationic ruthenium porphyrin complex was found to be an efficient catalyst for the Friedel-Crafts type reaction of arenes with imines. The use of a structurally rigid tetradentate porphyrin as the equatorial ligand and weakly coordinating axial ligand is the key to bring out the catalytic reactivity of ruthenium for the reaction.
In this paper, N-Boc and N-Cbz protected alpha-branched amines are synthesized directly from commercially available aromatic/heteroaromatic compounds, aldehydes, and tert-butyl or benzyl carbamate bearing a variety of substituents. Bismuth(III) triflate is found to be a highly effective catalyst for this one-pot, three-component coupling reaction. In addition, the use of mild reaction conditions, low catalytic loading, easy removal of the N-protective group, and one-step synthesis under open-flask are advantages of the present procedure.
Iodine-catalyzed, one-pot, three-component aza-Friedel–Crafts reaction of electron-rich arenes with aldehyde/carbamate combinations
Iodine is shown to be an efficient catalyst for a one-step, three-component aza-Friedel-Crafts reaction of activated arenes or heteroarenes with benzyl or tert-butyl carbamates in combination with a wide variety of aldehydes in toluene under 'open-flask' and mild conditions. In the presence of 5 mol % of iodine in toluene at room temperature, the reaction gives the corresponding N-CBz or N-Boc protected a-branched amines, selectively, in good to excellent yields. (C) 2012 Published by Elsevier Ltd.
NIS-Assisted Aza-Friedel-Crafts Reaction with α-Carbamoysulfides as Precursors of<i>N</i>-Carbamoylimines
AbstractA general and practical N‐iodosuccinimide (NIS)‐promoted aza‐Friedel–Crafts reaction of various aromatic nucleophiles with N‐acylimines generated in situ from α‐amidosulfides to give a rapid access to highly functionalized amines is described. The newly developed methodology is very mild, fast, efficient, and complementary.
Facile synthesis of nonsymmetrical heteroaryl-substituted triarylmethanes via the FeCl<sub>3</sub>·6H<sub>2</sub>O-catalyzed two-step Friedel–Crafts-type reaction
diarylmethyl carbamate with heteroaromatic compounds under “open-flask” at room temperature was also performed. The two-step reaction was especially useful for the synthesis of functionalized nonsymmetrical heteroaryl-substitutedtriarylmethanes in good yields under an air atmosphere at room temperature.
Cationic ruthenium porphyrin complex was found to be an efficient catalyst for the Friedel-Crafts type reaction of arenes with imines. The use of a structurally rigid tetradentate porphyrin as the equatorial ligand and weakly coordinating axial ligand is the key to bring out the catalytic reactivity of ruthenium for the reaction.