Complex chromene derivatives through a silver-catalysed cascade reaction of simple o-alkynylsalicylaldehydes and alkenes

The silver-catalysed reaction of simple ortho-alkynylsalicylaldehydes and alkenes gives complex benzo[de]chromenyl ketones through an unusual cascade process where the starting ortho-alkynylsalicylaldehyde behaves as a bis-diene derivative that participates in two different formal [4+2]-cycloaddition reactions.