Aspicilia gibbosa

A formal total synthesis of (+)-aspicilin, an 18-membered ring lactone isolated from the lichen Aspicilia gibbosa, is accomplished by the FDP aldolase protocol.46 The three carbon chain extension of benzyl protected 4-hydroxy-butanal is achieved with DHAP under the influence of FDP aldolase. The acid... 

Aspicilin (37), the first macrocyclic lactone isolated from a lichen 189), would appear to be biogenetically related to the hydroxyacids (36). Huneck and ScHREiBER 189) isolated aspicilin from Aspicilia gibbosa and established the structure (37) by analysis of the spectroscopic properties, chemical interconversions and properties of the derivatives so obtained (Scheme 6). Hence oxidation of aspicilin (37) gave the diacid (38) while catalytic reduction gave dihydroaspicilin (39). Subsequent saponification of (39) gave 4,5,6,17-tetrahydroxystearic acid (40). 

Aspicilin, the first macrocyclic lactone from a lichen Aspicilia gibbosa Korb.) is4,5,6-trihydroxyoctadec-2-en-l, 17-olide(l 18)(Huneckera/., 1973). 

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