A transition-metal-free fast track to flavones and 3-arylcoumarins.

A highly regioselective and transition-metal free one-pot arylation of chromenones with arylboronic acids has been achieved employing K2S2O8. The procedure consists of a sequence of some reactions including an arylation/decarboxylation cascade and proceeds well in aqueous media to afford biologically interesting flavones and 3-arylcoumarins. This method exhibited excellent selectivity and functional group tolerance under mild conditions. The reaction also showed perfect efficacy for the preparation of styryl coumarins.