Expeditious assembly of a 2-amino-4H-chromene skeleton by using an enantioselective Mannich intramolecular ring cyclization-tautomerization cascade sequence

Synthesis and biological evaluation of new pyranopyridine derivatives catalyzed by guanidinium chloride-functionalized γ-Fe2O3/HAp magnetic nanoparticles

Herein, we described the synthesis of γ-Fe₂O₃@HAP-GndCl MNPs as an efficient and recyclable nanocatalyst for synthesis of new pyranopyridine derivatives under solvent-free condition and then evaluated for theirs antioxidant and antifungal activities.

An enantioselective cascade reaction between α,β-unsaturated aldehydes and malonic half-thioesters: a rapid access to chiral δ-lactones

We disclose a novel efficient enantioselective organocatalytic cascade reaction for the preparation of δ-lactones in good to excellent yields (69-93%) and with high to excellent enantioselectivities (88-96% ee).

Highly mild approach towards synthesis of tetrasubstituted thiophenes by an organic salt afforded by cyclic thioureas and ketene dithioacetals

An organic salt generated by cyclic thioureas and 2-di(methylsulfanyl)methylenemalononitrile in reaction with primary and secondary α-haloketones leads to tetrasubstituted thiophenes without using additional base or catalyst at room temperature.

Synthesis of functional 4H-chromenes from phenols and acetophenones under solvent- and metal-free conditions

Sulfuric-acid-promoted tandem reaction of phenols with acetophenones under solvent- and metal-free conditions has been developed, which afforded functional 4H-chromenes in good yields with water as the side product.

Organocatalyzed enantioselective synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carboxylates

The organocatalyzed enantioselective synthesis of biologically active 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carboxylate derivatives was achieved using bifunctional cinchona alkaloids as the catalysts. Using quinine thiourea as the catalyst, the tandem Michael addition-cyclization reaction between 1,3-cyclohexanediones and alkylidenecyanoacetate derivatives gives the desired products in high yields (up to 92%) and good ee values (up to 82%).