To a solution of (S)-2-(tert-butoxycarbonylamino)-3-phenylpropanoic acid (1.03 g, 3.81 mmol) in THF (70 mL), are added DCC (1.03 g, 4.91 mmol), HOBt (660 mg, 4.90 mmol) and 3(R)-quinuclidinol (1.18 g, 9.48 mmol) and the resulting mixture is stirred for 12 hours at RT under nitrogen flowstream (LC-MS monitoring: complete conversion). The solvent is evaporated and the residue is partitioned between EtOAc (100 mL) and 2M K2CO3 (50 mL); the organic layer is separated, washed with brine and dried over Na2SO4. The resulting crude is purified by flash chromatography (DCM/MeOH=95/5, 0.1% NH3 (aq.)) to obtain 1.12 g of I19 (80% yield).
