A novel HAuCl4@UiO-66-NH2 material has been obtained and utilized as a heterogeneous Au(III) catalyst. This Au(III) catalyst was able to promote the formation of a variety of dihydrochalcones starting from 2H-chromenes in moderate to good yields. A tandem hydride shift/hydration reaction sequence has been proposed based on deuterium labeling studies, which revealed a 1,5-hydride shift reaction ...

A series of optically active pyrano[3,2-c]chromenes have been synthesized through an asymmetric domino reaction of 4-hydroxy-2H-chromen-2-ones with malononitriles. The targeted molecules were obtained in excellent yields and enantioselectivities (up to 94% yield, 99% ee). The AChE inhibitory activity studies revealed that compounds 4n (IC50 = 21.3 μM) and 4p (IC50 = 19.2 μM) displayed potent ac...

The reactions of 2-perfluoroacyl-1H-benzo[f]chromenes and 6,7-dimethyl-3-trifluoroacetyl-4H-chromene with primary aliphatic amines ammonia afforded a series enamino ketones containing (2-hydroxynaphthalen-1-yl)methyl or 2-hydroxybenzyl substituent in the ?-position respect to carbonyl group. These involved opening pyran ring, which followed aza-Michael addition as initial step. obtained were fo...

An efficient entry to the preparation of elusive 4-unsubstituted-3-iodo-2H-chromenes has been accomplished as result of a catalytic cyclization. Thus, upon exposition of [(3-iodoprop-2-yn-1-yl)oxy]arenes to IPrAuNTf2 (3 mol %), in 1,4-dioxane at 100 °C, the desired heterocyclic motif is readily assembled. This process nicely tolerates a variety of functional groups and, interestingly, it is com...

An efficient chiral squaramide-catalysed enantioselective Michael addition of pyrazolin-5-ones to 3-nitro-2H-chromenes for the synthesis of chiral heterocyclic systems containing both chroman and pyrazolone derivatives has been developed. This reaction afforded the desired products in high to excellent yields (up to 98%) with high enantioselectivities (up to 96%) and excellent diastereoselectiv...

Silica-bonded n-propyltriethylene-tetramine (SBNPTT) was found as an efficient solid base for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromenes. Chromene derivatives were obtained via the three-component condensation reaction of aromatic aldehydes, malononitrile, and dimedone at 80 oC under solvent-free conditions. The heterogeneous solid base showed much the same efficiency when u...

The reactive intermediate generated by the addition of tert-butyl and 1,1,3,3-tetramethyl butyl isocyanide and cyclohexyl isocyanide to dialkyl acetylenedicarboxylate was trapped by 3-hydroxy pyridine to produce highly functionalized 4H-chromenes in fairly good  yields

The reactive intermediate generated by the addition of tert-butyl and 1,1,3,3-tetramethyl butyl isocyanide and cyclohexyl isocyanide to dialkyl acetylenedicarboxylate was trapped by 3-hydroxy pyridine to produce highly functionalized 4H-chromenes in fairly good  yields.