A solution of 4-bromo-9a-butyl-8-chloro-7-methoxy-1,2,9,9a-tetrahydro-3H-fluoren-3-one (103 mg, 0.268 mmol) in anhydrous 1-methyl-2-pyrrolidinone (0.54 mL) was treated with copper(I) cyanide (24 mg, 0.268 mmol). The mixture was placed under a nitrogen atmosphere, stirred, and heated in an oil bath at 150° C. for 1.5 hours. After cooling to room temperature, the mixture was partitioned between EtOAc (50 mL) and water (50 mL). The organic phase was washed with water (5×50 mL) and brine (50 mL), dried over MgSO4, filtered, and evaporated under vacuum to an oil. The crude product was purified by preparative layer chromatography on a 0.1×20×20 cm silica gel GF plate, developing with 5% EtOAc in CH2Cl2. The product band was eluted with EtOAc and the eluent evaporated under vacuum to afford 9a-butyl-8-chloro-4-cyano-7-methoxy-1,2,9,9a-tetrahydro-3H-fluoren-3-one (65 mg) as an oil.
