Synthetic studies towards the benzophenone precursor for balanol

Synthesis of 4-carboxy-2,6-dimethoxyphenyl 2′-carboxy-6′-methoxyphenyl ketone, an important precursor for balanolʹs benzophenone portion, has been achieved via a short and efficient route in three steps using ortho-lithiation as the key step. In another approach aromatization of 2-(2′-methoxy-6′-methylbenzoyl)-5-methyl-1,3-cyclohexanedione afforded benzophenone precursor 2,6-dimethoxy-4-methylphenyl 2′-methoxy-6′-methylphenyl ketone along with the formation of substituted xanthone.