To a mixture of Pd(OAc)2 (0.054 g, 0.2 mmol), NaOtBu (0.64 g, 6.6 mmol) in xylene (7.0 mL) in a screw-capped tube was added tBu3P (0.049 g, 0.2 mmol). After 10 minutes a solution of 5-bromo-1-(tert-butyl-dimethyl-silanyl)-1H-indole (1.30 g, 4.4 mmol) in xylene (7.0 mL) and a solution of 3-benzyl-piperazine-1-carboxylic acid tert-butyl ester (1.34 g, 4.8 mmol) in xylene (8.0 mL) were added. The mixture was heated to 80° C. for 30 minutes, then cooled to room temperature. The reaction mixture was taken up in ethyl acetate, filtered through a pad of celite, and concentrated under reduced pressure. Purification via flash chromatography (gradient: 2% to 20% EtOAc in hexane) afforded 3-Benzyl-4-[1-(tert-butyl-dimethyl-silanyl)-1H-indol-5-yl]-piperazine-1-carboxylic acid tert-butyl ester (1.65 g, 74%) as a pale yellow solid; MS (M+H)=506.
