Diastereoselective Synthesis of Polycyclic Acetal-Fused Pyrano[3,2-c]pyran-5(2H)-one Derivatives

A facile and efficient diastereoselective one-pot synthesis of polycyclic acetal-fused pyrano[3,2-c]pyrane-5(2H)-one was achieved through the annulation reaction of 2-C-formyl glycals with various 4-hydroxycoumarins and 4-hydroxy-6-methyl-2H-pyran-2-one. The asymmetric induction was significantly influenced by the C-4 stereogenic center of 2-C-formyl glycals. The resulting polycyclic acetal-fused pyranopyrones demonstrated anticancer activities.