Discovery of an in situ carbocationic system using trityl chloride as a homogeneous organocatalyst for the solvent-free condensation of β-naphthol with aldehydes and amides/thioamides/alkyl carbamates in neutral media

Trityl chloride (TrCl), efficiently catalyzes the one-pot multi-component condensation of beta-naphthol with aromatic aldehydes and amides/thioamides/carbamates such as acetamide, benzamide, nicotinamide, thioacetamide, and methylcarbamate under solvent-free and neutral conditions to afford 1-amido-alkyl-2-naphthols, 1-thioamido-alkyl-2-naphthols, and 1-carbamato-alkyl-2-naphthols in high yields and very short reaction times. Mechanistically, it is interesting that trityl chloride through the in situ generation of trityl carbocation with inherent instability is efficient as a reusable homogeneous organocatalyst in neutral media. (C) 2012 Elsevier Ltd. All rights reserved.