Molecular iodine-catalyzed diastereoselective synthesis of cis-fused pyranobenzopyrans and furanobenzopyrans

Abstract A highly efficient method for the diastereoselective synthesis of cis-fused pyranobenzopyrans and furanobenzopyrans via 2 mol % of molecular iodine-catalyzed reaction of o -hydroxybenzaldimines with 3,4-dihydro-2 H -pyran and 2,3-dihydrofuran at ambient temperature is described. 2-Butoxy-4- N -arylaminobenzopyrans were also synthesized from o -hydroxybenzaldimine and n -butyl vinyl ether using this procedure.