Iodoethane (14 μL, 0.18 mmol) was added to (4S,7R)-2-(2-chloro-phenyl)-7,8,8-trimethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (Intermediate 10; 47 mg, 0.16 mmol) and potassium carbonate (43 mg, 0.31 mmol) in dimethylformamide (1 mL). The mixture was heated at 60 degrees for 4 h, and then stirred at room temperature over the weekend. The reaction mixture was diluted with ethyl acetate and washed with NaOH. The solvent was evaporated from the ethyl acetate layer and the residue was purified by flash chromatography, eluting with 0-70% ethyl acetate/hexanes, to give 2-(2-chloro-phenyl)-3-ethoxy-7,8,8-trimethyl-4,5,6,7-tetrahydro-2H-4,7-methano-indazole (12.3 mg, 16%) and (4S,7R)-2-(2-chloro-phenyl)-1-ethyl-7,8,8-trimethyl-1,2,4,5,6,7-hexahydro-4,7-methano-indazol-3-one (4.4 mg, 9%). APCI-MS (M+H) 331.
