Gold nanoparticles supported on TiO(2) (~1%) catalyse in high yields the selective cycloisomerisation of aryl propargyl ethers into the corresponding 2H-chromenes, under heterogeneous conditions. 2H,2'H-3,3'-Bichromenes resulting from a catalytic oxidative dimerization pathway are also formed as by-products.

ABSTRACT A simple and efficient approach has been developed to synthesise novel functionalised 5H-chromeno[2,3-d] pyrimidines derivatives (4a-h). This entails treating 2-amino-3-cyano-4H-chromenes (3a-h) with formamidine acetate under microwave irradiations solvent-free conditions. All structures of new compounds obtained in this study were characterised by IR, MS, 1H 13C NMR analysis. Addition...

A series of photochromic 2,2,4,6-tetraaryl-2 H -benzo[ h ]chromenes have been efficiently synthesised by two complementary strategies employing the condensation 1,1,3-triarylprop-2-yn-1-ols with 4-substituted 1-naphthols and Suzuki cross-coupling chemistry. The novel 1,1,3-triarylpropynols were readily obtained either addition an arylacetylide to requisite benzophenones or a Sonogashira couplin...

Highly enantioselective synthesis of chiral chromenes and tetrahydroquinolines is achieved by combining asymmetric copper-catalyzed allylic substitution with Grignard reagents and an efficient intramolecular Heck reaction. Moreover, the exocyclic double bond formed in the cyclisation was subjected to RCM, hydroboration and hydrogenation illuminating the synthetic versatility of these heterocycles.

A highly enantioselective (S)-diphenylpyrrolinol triethylsilyl ether promoted tandem oxa-Michael-aldol reaction of alpha,beta-unsaturated aldehydes with salicylaldehydes has been developed; the method affords one-pot access to chiral and synthetically useful chromenes in high yields and high enantioselectivities from readily available compounds.