Condensation of diketone (I) with the organocerium reagent derived from ethylmagnesium bromide and CeCl3 afforded the oxaadamantanol (II), which was further converted to mesylate (III) upon reaction with methanesulfonyl chloride and Et3N. Subsequent fragmentation of (III) by treatment with silica gel in CH2Cl2 produced bicyclic enone (IV). This was condensed with 2-amino-4-methylbenzonitrile (V) in the presence of AlCl3 in refluxing 1,2-dichloroethane to furnish the target tetracyclic derivative. Resolution was then achieved by chiral MPLC.
Condensation of diketone (I) with the organocerium reagent derived from methylmagnesium bromide and CeCl3 afforded the oxaadamantanol (II), which was further converted to mesylate (III) upon reaction with methanesulfonyl chloride and Et3N. Subsequent fragmentation of (III) by treatment with silica gel in CH2Cl2 produced bicyclic enone (IV). This was condensed with 2-amino-4-fluorobenzonitrile (V) in the presence of AlCl3 in refluxing 1,2-dichloroethane to furnish the target tetracyclic derivative. Resolution was then achieved by chiral MPLC.
Condensation of diketone (I) with the organocerium reagent derived from methylmagnesium bromide and CeCl3 afforded the oxaadamantanol (II), which was further converted to mesylate (III) upon reaction with methanesulfonyl chloride and Et3N. Subsequent fragmentation of (III) by treatment with silica gel in CH2Cl2 produced bicyclic enone (IV). This was condensed with 2-aminobenzonitrile (V) in the presence of AlCl3 in refluxing 1,2-dichloroethane to furnish the target tetracyclic derivative. Resolution was then achieved by chiral MPLC.