Total Synthesis of the Enantiomerically Pure Lichen Macrolide (+)‐Aspicilin

The title compound 1 contains an 18-membered lactone ring, four centers of chirality, and a CC double bond. It was synthesized in enantiomerically pure form starting from the inexpensive chemicals phenol, azelaic acid, and the ethyl ester of (S)-lactic acid. The key step of the synthesis is a (presumably broadly applicable) photochemical reaction.—It is remarkable how far information can be transferred from the center of chirality already present (C-17) to the new center of chirality (C-6).