To a mixture of zinc powder (5.52 g, 84.5 mmol) and Celite (1.1 g) in N,N-dimethylacetamide (14 ml) was added dropwise chlorotrimethylsilane (0.930 ml, 7.33 mmol) in 1,2-dibromoethane (0.665 ml, 7.54 mmol) at 0° C. under nitrogen atmosphere. The mixture was warmed to room temperature, and stirred for 20 minutes. 8-Iodo-1,4-dioxa-spiro[4.5]decane (18.1 g, 67.6 mmol) in N,N-dimethylacetamide (34 ml) was then added dropwise at 0° C. The mixture was stirred for 30 minutes at room temperature, and the supernatant solution was added dropwise to the mixture of (4-bromobenzyloxy) (tert-butyl)dimethylsilane (15.7 g, 52.0 mmol), copper iodide(I) (792 mg, 4.16 mmol) and [1,1′-bis(diphenylphosphino) ferrocene]dichloropalladium(II)dichloromethane complex (1.70 g, 2.08 mmol) in N,N-dimethylacetamide (74 ml) at room temperature under nitrogen atmosphere. The mixture was stirred at 80° C. for 5 hours. The mixture was poured into the cold water, and extracted with ethyl acetate. The organic layer was washed with water (three times), dried over sodium sulfate, and concentrated in vacuo. The residue was purified by silica gel column chromatography (eluent; hexane/ethyl acetate=92/8) to afford tert-butyl-[4-(1,4-dioxa-spiro[4.5]dec-8-yl)benzyloxy]dimethylsilane as a pale yellow oil (14.0 g, 38.6 mmol, 74%).
