Ru(II) complexes bearing tertiary phosphine ligands: a novel and efficient homogeneous catalyst for one‐pot synthesis of dihydropyrano[3,2‐<i>c</i>]chromene and tetrahydrobenzo[<i>b</i>]pyran derivatives

Abstract

A number of ruthenium complexes were prepared and their catalytic activities in three‐component one‐pot condensation of aldehydes, malononitrile and 4‐hydroxycoumarin or dimedone was considered to afford dihydropyrano[3,2‐ c ]chromenes and tetrahydrobenzo[ b ]pyran derivatives under optimum reaction conditions. We found that a catalytic amount of RuBr 2 (PPh 3 ) 4 efficiently promotes the reaction in a short time (3–15 min) and with high yield (75–88%). Copyright © 2012 John Wiley &amp; Sons, Ltd.