The synthesis of several new xanthenes based on the 1,3-dicarbonyl scaffolds lawsone and coumarin was developed using tandem three-component reactions involving the reagents ortho-hydroxybenzaldehyde, as bifunctional reagent, and an appropriate thiol. These reactions generated two series of para- and ortho-naphthoxanthenes that are structurally related to α- and β-pyranaphthoquinones and one series of coumarin-xanthene derivatives.
Keywords:
2-hydroxy-1,4-naphthoquinone; coumarin; multi-component reactions; organocatalysis; ortho-quinone methide
