1.00 g (4.04 mmol) 2-(4-Piperidin-4-yl-phenyl)-propionic acid methyl ester (XI.3) are added to a mixture of 813 mg (4.04 mmol) 1-bromo-4-ethoxy-benzene, 1.60 g (97%, 16.2 mmol) sodium tert-butyrat, 483 mg (1.62 mmol) 2-(di-tert-butylphosphino)biphenyl and 370 mg (0.40 mmol) tris-(dibenzylidenaceton)-dipalladium(0) in 10 mL 1,4-dioxane. The mixture is stirred for 12 h at 70° C. After that time, the precipitate is filtered off and washed with ACN and diethyl ether. The residue is purified by HPLC (column: Waters XBridge 50; eluent A: water+0.3% NH4OH, eluent B: MeOH) to yield the desired product.
