To 0.50 g (1.54 mmol) trifluoro-methanesulfonic acid 4-(2-acetylamino-propyl)-phenyl ester (I53.2) and 0.32 g (2.00 mmol) 4-tert.butylphenylacetylen in 3.0 mL water and 3.0 mL sec-butylamine are added 0.10 g (0.14 mmol) bis(triphenyphosphine)dichloropalladium and the mixture is stirred at r.t. for 4 h and at 80° C. for 1 h. The reaction mixture is allowed to cool to r.t. and is then partitioned between EtOAc and citric acid (10% in water). The organic layer is dried with Na2SO4 and the solvent is removed in vacuo. The residue is purified twice by column chromatography (silica gel; DCM/MeOH 9/1 and aluminium oxide DCM/EtOAc 4/1). The resulting product is triturated with MeOH.
