A carboxylic acid, an aldehyde, and an isonitrile were combined in a single step (Passerini reaction) under mechanochemical activation to produce several α‐acyloxycarboxamide derivatives in high to excellent yields within 15 min of milling. Mechanochemistry, when combined with the diversity provided by multicomponent reactions, enables the efficient synthesis of the target compounds, with great atom economy, shorter reaction times, and experimental simplicity. The method allows for the rapid production of a vast library of complex compounds from a limited number of substrates.

In the search for convenient, green, and practical catalytic methods for the current interest in organic synthesis, a simple, green, and highly efficient protocol for N-formylation of various amines was carried out in the presence of immobilized sulfuric acid on silica gel (H₂SO₄–SiO₂). All reactions were performed in refluxing triethyl orthoformate (65 °C). The product formamides were obtained with high-to-excellent yields within 4 min to 2 h. The current approach is advantageous, due to its short reaction time and high yields. The catalyst is recyclable with no significant loss in catalytic efficiency.

A protocol based on the Passerini Multi‐Component reaction (MCR) has been developed for facile, efficient, environmentally benign and atom economical synthesis of a small library of biologically important oxindole derivatives employing isatin, benzoic acid and substituted isocyanides. In contrast to the conventional approach, which requires the use of toxic organic solvents, Passerini reactions were completed in 10–15 minutes under mechanochemical conditions with excellent yields. The protocol described below allows the modular synthesis of diverse compounds under green chemistry principles, specifically in favourable environmental conditions, with great atom economy, shorter reaction time, cleaner reactions with improved yields, and experimental simplicity.

A simple, green, and highly efficient protocol for the synthesis of isocyanides is described. The reaction involves dehydration of formamides with phosphorus oxychloride in the presence of triethylamine as solvent at 0 °C. The product isocyanides were obtained in high to excellent yields in less than 5 min. The method offers several advantages including increased synthesis speed, relatively mild conditions, and rapid access to large numbers of functionalized isocyanides, excellent purity, increased safety, and minimal reaction waste. The new approach of synthesising dehydrative isocyanides from formamides is significantly more environmentally-friendly than prior methods.

The application of immobilized sulfuric acid on silica gel (H₂SO₄-SiO₂) as an efficient and easily reusable solid catalyst was explored in the synthesis of novel α-acyloxycarboxamide derivatives via a Passerini reaction of benzoic acid, aldehyde/ketone, and isocyanides. The Passerini adducts were obtained in high to excellent yields within 10 min in aqueous media under catalytic conditions. The key advantages of the process include a short reaction time, high yields, the catalyst’s low cost, and the catalyst’s reusability.

N -Formamides as carbonyl precursors in the synthesis of Passerini adducts under mechanochemical conditions.