A diastereoselective synthesis of tetrahydro- and dihydro-pyrido[2,3-c]coumarin derivatives via a one-pot three-component Povarov reaction catalyzed by bismuth(III) chloride.

A diastereoselective synthesis of tetrahydro- and dihydro-pyrido[2,3-c]coumarin derivatives has been achieved via a one-pot three-component aza-Diels-Alder reaction of aromatic aldehydes, 3-aminocoumarin and dienophiles catalyzed by BiCl. NOE studies proved that exo-isomers were obtained in all cases with high selectivity. The reaction proceeded at room temperature providing good yields of products as well as applicability on a wide range of substrates.