The Ugi-Smiles and Passerini-Smiles couplings: A story about phenols in isocyanide-based multicomponent reactions

The Ugi-Smiles and Passerini-Smiles couplings are extensions of Ugi and Passerini reactions involving the use of acidic phenols in place of the traditional carboxylic acid partners. A Smiles rearrangement is in each case responsible for the final N-aryl carboxamide formation. All the available data on the mechanisms and the scope of these reactions are presented. To demonstrate the interest of Ugi-Smiles and Passerini-Smiles couplings, these reactions have been further applied to the preparation of various fused heterocyclic systems. These "post-condensation" studies are also covered in this review.