Studies on the Synthesis of Landomycin A. Synthesis of the Originally Assigned Structure of the Aglycone, Landomycinone, and Revision of Structure William R. Roush R. Jeffrey Neitz 10.1021/jo049426c.s001 https://acs.figshare.com/articles/journal_contribution/Studies_on_the_Synthesis_of_Landomycin_A_Synthesis_of_the_Originally_Assigned_Structure_of_the_Aglycone_Landomycinone_and_Revision_of_Structure/3331159 The originally proposed structure (<b>2</b>) 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 <b>2</b> features the Dötz benzannulation reaction of chromium carbene <b>5</b> and alkyne <b>6</b>, and the intramolecular Michael-type cyclization reaction of the phenolic naphthoquinone <b>20</b>. It is proposed that natural landomycinone possesses the alternative structure <b>3</b>, but attempts to access this structure via the Michael-type cyclization of the isomeric phenolic naphthoquinone <b>38</b> have been unsuccessful. 2004-07-23 00:00:00 chromium carbene 5 isomeric phenolic naphthoquinone 38 cyclization Assigned Structure D ötz benzannulation reaction landomycin alternative structure 3 2 features aglycone phenolic naphthoquinone 20 alkyne 6 Synthesi landomycinone