A Novel Method for Preparing Chromones via 1,2-Migration of α-Diazo-Flavanones

Abstract A novel method for preparing chromones from α-diazo-flavanones has been developed. Good yields and regioselectivity are obtained through HCl catalysis and Rh2(Oct)4 catalysis. The chromone obtained can undergo a one-pot Diels–Alder reaction to synthesize flavanone propellane in high yield. Mechanisms about 1,2-migration under both catalysts are proposed.