C‐Glycosyl Juglone in Angucycline Synthesis: Total Synthesis of Galtamycinone, Common Aglycon of C‐Glycosyl Naphthacenequinone‐Type Angucyclines.

Abstract A two-step access to C -glycosyl juglones, 16 and 17 , useful intermediates toward the angucyclines, either benz[ a ]anthraquinone-type or naphthacenequinone-type, has been developed based on (1) the O → C -glycoside rearrangement and (2) the regioselective cycloaddition of α-alkoxybenzyne and α-oxyfuran. The first total synthesis of galtamycinone ( 2 ), the common aglycon of naphthacenequinone-type angucyclines, has been achieved by utilizing 17 as the key intermediate.