Synthesis of 9-Deoxynanaomycin a Methyl Ester1

The tricyclic intermediate 6 prepared in three steps from 1,4-dimethoxynaphthalene was utilized in preparing alkene 7. Cleavage of the double bond of 7 furnished the keto aldehyde 9 which was transformed to the unsaturated ester 13. The ester 13 on heating with KOH-MeOH furnished the acid 14a whose methyl ester was oxidised to 9-deoxynanaomycin A methyl ester (2).