Propargylic Phosphonium Salts in Cobalt-Catalysed Diels-Alder Reactions

A straight forward one-pot reaction sequence consisting of a cobalt-catalysed Diels-Alder reaction for the generation of a dihydroaromatic phosphonium salt and a subsequent Wittig olefination generates polysubstituted dihydrostilbene derivatives which can optionally be oxidised by DDQ to the corresponding stilbenes. Several aldehydes, 1,3-dienes and also homopropargylic phosphonium salts can be applied.