Synthesis of New Lichen Xanthones

The unambiguous total synthesis of seventeen chlorine-containing derivatives of norlichexanthone (1,3,6-trihydroxy-8-methyl-9H-xanthen-9-one) has been achieved by using the condensation of an appropriately substituted methyl or ethyl orsellinate and phloroglucinol or 2-chlorophloroglucinol in the key step.