Synthesis of Further b-Ketoalkyl Lichen Depsides

Abstract

The unambiguous total synthesis of the lichen depsides 2-O-methylglomelliferic acid (39), 4-O- methylhyperolivetoric acid (40), hyperconfluentic acid (41), microphyllinic acid (42), arthoniaic acid (43), 2′-O-methylmicrophyllinic acid (44), 2′-O-methylhyperphyllinic acid B (45), 4-O-methylsuperolivetoric acid (46), 2′-O-methylhyperphyllinic acid A (47), 2′-O-methylnorsuperphyllinic acid (48) and 4-O- methyloxocryptochlorophaeic acid (49) has been achieved by the condensation of an appropriately substituted orsellinic acid and protected phenol in the key step, followed by deprotection.