A metal-free tandem C–C/C–O bond formation approach to densely functionalized indolyl $$4H$$ 4 H -chromenes catalyzed by polystyrene-supported $$p$$ p -toluenesulfonic acid under solvent-free conditions

Novel Synthetic Approach for the Access of Functionalised 4H-Chromenes

A simple, efficient and high-yielding one-pot protocol for the synthesis of novel functionalised 4H-chromenes and chromene carboxylic acids has been developed using multi-component domino coupling reactions of anil-like compounds with 1,3-diketones and indole in the presence of formic acid catalyst under solvent-free conditions. The protocol avoids the use of expensive catalysts, toxic solvents and chromatographic separation.

Extending the scope of oleic acid catalysis in diversity-oriented synthesis of chromene and pyrimidine based scaffolds

Readily available, non-toxic, biodegradable oleic acid was found to catalyse 4H-chromene derivatives syntheses in good yields in a water medium.

One-pot synthesis of tetrahydro-4H-chromenes by supramolecular catalysis in water

Tetrahydro-4H-chromenes were synthesizedviaan efficient one-pot three-component protocol by supramolecular catalysis with β-cyclodextrin in water.