This invention provides cancer-active tricyclic and tetracyclic oxypyrones and a method of synthesizing these compounds. Preferred compounds have aryl groups at the 3-position of the oxypyrone ring. The tricyclic oxypyrone synthetic method is a simple condensation reaction of pyrones with cyclohexenecarboxaldehydes, providing high yields and using few steps. The tetracyclic oxypyrone synthetic method is a simple condensation reaction of carvones with pyrones.