K 2 CO 3 -Promoted oxy-Michael Addition/Cyclization of α , β -Unsaturated Carbonyl Compounds with Naphthols: Synthesis of Naphthopyrans.

A potassium carbonate promoted tandem oxy-Michael addition/cyclization of α , β -unsaturated carbonyl compounds with naphthol derivatives for the synthesis of 2-substituted naphthopyrans was developed. Using the readily available, inexpensive potassium carbonate as the promoter, a range of different substituted naphthopyrans were prepared.