To a solution of 3-benzo[1,3]dioxol-5-yl-5-(4-methoxy-benzyloxy)-benzonitrile (250 mg) in anhydrous THF (3 mL) were added a solution of ethylmagnesium chloride (517 μL of 2 M solution in diethyl ether) and catalytic amount of cuprous bromide (2 mg). The resulting reaction mixture was refluxed for 1 h and then additional amount of ethylmagnesium chloride (517 μL of 2 M solution in diethyl ether) was added and heating was continued for 30 min. After it was cooled down, 10% sulfuric acid (1.5 mL) was added and stirring was continued for 30 min at room temperature. Then the reaction mixture was diluted with diethyl ether, washed with water and brine. The organic extract was dried over anhydrous sodium sulfate, concentrated and purified on a silica gel column using ethyl acetate and hexanes to yield 136 mg of the title compound (50% yield). HRMS calcd for C24H22O5 [M+H]+ 391.1540, observed 391.1541.
