Tandem Diels-Alder/oxidation-aromatization reactions involving 2-styrylchromones and arynes

Transition-metal-free Diels-Alder and tandem Diels-Alder/oxidation-aromatization reactions of 2-styrylchromones with arynes have been demonstrated under mild reaction conditions with a wide range of substrates. The tandem process afforded functionalized benzo[c]xanthone derivatives in moderate to good yields. This efficient protocol allows rapid access to either dihydrobenzo[c]xanthone and benzo[c]xanthone derivatives selectively by simply changing the atmosphere of the reaction.