To a degassed solution of 0.35 g (1.0 mmol) of 2-bromo-5,6-dihydro-5,5-dimethyl-8-(phenylthio)-naphthalene (Compound A35) and 0.34 g (1.9 mmol) of ethyl 4-vinylbenzoate in 4.0 mL of triethylamine, was added 0.066 g (0.2 mmol) of tri-o-tolylphosphine and then 0.025 g (0.1 mmol) of palladium(II) acetate. The reaction was heated at 90° C. for 2.25 h. The reaction was concentrated in vacuo. The residue was purified by flash chromatography (silica, 5% ethyl acetate in hexane), followed by recrystallization using EtOH to afford the title compound as white crystals.
