Metal- and solvent-free synthesis of aniline- and phenol-based triarylmethanes via Brönsted acidic ionic liquid catalyzed Friedel-Crafts reaction

Friedel-Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs)

An iron(III) chloride hexahydrate-catalyzed Friedel-Crafts acylation of benzene derivatives in tunable aryl alkyl ionic liquids (TAAILs) has been developed. Through optimization of the metal salt, reaction conditions and ionic liquids, we were able to design a robust catalyst system that tolerates different electron-rich substrates under ambient atmosphere and allows for a multigram scale.

Enabling Sustainable Chemistry with Ionic Liquids and Deep Eutectic Solvents: A Fad or the Future?

Ionic liquids (ILs) and deep eutectic solvents (DESs) debuted with a promise of a superior sustainability footprint due to their low vapor pressure. However, their toxicity and high cost compromise this footprint, impeding their real-world applications. Fortunately, their property tunability through a rational selection of precursors, including bioderived ones, provides a strategy to ameliorate toxicity, lower cost, and endow new functions. This Review discusses whether ILs and DESs are sustainable solvents and how they contribute to sustainable chemical processes.

Lewis-Acid-Catalyzed Selective Friedel-Crafts Reaction or Annulation between Anilines and Glyoxylates

A Lewis-acid-catalyzed selective reaction between anilines and glyoxylates was developed for synthesis of diarylmethanes or oxoimidazolidines. Under the catalysis of AgOTf, a series of anilines-based diarylmethanes, including primary, secondary, and tertiary anilines, were obtained in moderate to good yields. Moreover, stereoselective oxoimidazolidines were performed with the catalysis of Cu(OAc)₂·H₂O.

Brönsted Acidic Ionic Liquid Catalyzed Three-Component Friedel-Crafts Reaction for the Synthesis of Unsymmetrical Triarylmethanes

convenient and practical methodology for the synthesis of unsymmetrical triarylmethanes was demonstrated through a one-pot three-component double Friedel-Craft reaction between various aliphatic aromatic and heteroaromatic aldehydes, N,N-dialkylanilines and indoles using Bronsted acidic ionic liquid as catalyst. This method was successfully performed under metal- and solvent-free conditions at 80oC, affording the corresponding unsymmetrical triarylmethane products in moderate to high yields with a broad range of substrates. In addition, the mechanistic proposal of this methodology was studied by using quantitative NMR analysis (qNMR).