The A/B ring synthon 13, previously converted into daunomycinone (6) by Keay and Rodrigo, 6 has been prepared in seven steps and 38% overall yield using benzamide directed ortho metalation strategy. Significant steps are: the incorporation of a four-carbon Grignard unit (10) into 9, dibal reduction of 11, and intramolecular aldol condensation of the resulting product 12 to give the dihydronaphthalene 13.
