Efficient Construction of a 3C-Xanthone-Linked 3C-Chromone Scaffold by Novel Double Michael Additions and Cyclizations

A novel base-promoted cascade reaction of 2-methyl-3-(1-alkynyl)chromones to produce a 3C-xanthone-linked 3C-chromone scaffold has been developed. This tandem process involves multiple reactions such as Michael additions/cyclizations under mild conditions without a transition metal catalyst and inert atmosphere.