Synthesis of Decarboxythamnolic Acid The total synthesis of the meta-depside decarboxythamnolic ( = 3-[(3-formyl-2-4-dihydroxy-6-methyl-phenyl)oxy]-2-hydroxy-6-methoxy-4-methylbenzoic acid; 25) by the biomimetic condensation of the substituted β-orcinol units 9 and 22 is described.