Synthetic studies towards the total synthesis of olivin using Fischer carbene complexes: Synthesis of the 1,6,8-trioxygenated tricyclic core via the benzannulation reaction

A synthesis of a model for the tricyclic core of olivin is developed which begins with the benzannulation of a 2,4-dioxy-genated aryl Fischer carbene complex. Completion of the synthesis of the model system involves an intram olecular Friedel-Craffs cyclization and a triflate reduction of the oxygen substituent at the C-10 position. The proper choice of oxygen substituents on the carbene complex will permit this strategy to be utilized in the synt hesis of olivomycin A where the oxygens in the C-2 and C-6 positions will n eed to be differentiated.