The originally proposed structure (2) of landomycinone, the aglycone of landomycin A, has been synthesized and shown to be nonidentical to the naturally derived landomycin A aglycone. The synthesis of 2 features the Dötz benzannulation reaction of chromium carbene 5 and alkyne 6, and the intramolecular Michael-type cyclization reaction of the phenolic naphthoquinone 20. It is proposed that natural landomycinone possesses the ...