EFFICIENT ONE-STEP SYNTHESIS OF 2-ARYLFURANS BY CERIC AMMONIUM-NITRATE (CAN)-MEDIATED CYCLOADDITION OF 1,3-DICARBONYL COMPOUNDS TO ALKYNES

An efficient method for construction of 2-arylfurans has been develope d by ceric(IV) ammonium nitrate-mediated oxidative cycloaddition of cy clic and acyclic 1,3-dicarbonyl compounds to several alkynes. Reaction s of 1,3-cyclohexanedione, 1,3-cyclopentanedione, and 2,4-pentanedione with several alkynes furnish 2-arylfurans in 26-75% yields. Extension of this technology to more complex 4-hydroxy-2-quinolone and 3-hydrox y-1H-phenalen-1-one with phenylacetylene also affords furoquinolinone and furophenalenone derivative in moderate yields. Reaction of 4-hydro xycoumarins with phenylacetylene give linear and angular furocoumarin derivatives as a mixture of regioisomer in good yields. The mechanisti c pathway for the formation of 2-arylfurans has been also described.