Chromeno[4,3-b]chromene is a ubiquitous structural motif found in various pharmaceuticals and biologically active compounds. A concise palladium-catalyzed reaction of vinyl iodides and salicyl N-tosylhydrazones has been achieved to afford a series of compounds containing the chromeno[4,3-b]chromene scaffold in moderate to high yield. This tandem reaction involves palladium(II) carbene migratory insertion and intramolecular cyclization assisted by an O nucleophile and tolerates various functional groups.

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Ac onvenientp alladium-catalyzed tandem reactiono fa ryl iodides and salicyl N-tosylhydrazones has been achieved to afford as eries of compoundsc ontainingt he novels piro[benzofuran-3,2'-chromene] scaffold in moderate to good yields. This efficientc atalytic reaction, which tolerates various functional groups,c ombines alkyne-based 5exo-dig cyclization, palladium(II)c arbenem igratory insertion and intramolecular cyclization, generating three new bonds in one reaction.

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A convenient palladium‐catalyzed tandem reaction of aryl iodides and salicyl N‐tosylhydrazones has been achieved to afford a series of compounds containing the novel spiro[benzofuran‐3,2′‐chromene] scaffold in moderate to good yields. This efficient catalytic reaction, which tolerates various functional groups, combines alkyne‐based 5‐exo‐dig cyclization, palladium(II) carbene migratory insertion and intramolecular cyclization, generating three new bonds in one reaction.