To 1.0 g (4.57 mmol) iodoaniline in 30 mL acetonitrile were added 2.22 g (5.02 mmol) BOP, 1.78 g (4.57 mmol) azetidine-1,3-dicarboxylic acid monobenzyl ester (route 13, step a), 0.6 mL (4.57 mmol) triethylamine, and the mixture was stirred at room temperature for 16 hours. 0.6 mL (4.57 mmol) triethylamine was added and the mixture was stirred for 2 hours. 2.22 g (5.02 mmol) BOP was added and the mixture was stirred at room temperature for 16 hours. 30 mL 1 M aqueous Na2CO3 was added and the mixture was extracted with EtOAc (2×30 mL), the organic layers were combined, washed with 30 mL brine then dried with Na2SO4. After filtration and evaporation of the solvent the product was purified by column chromatography (silica, heptane/EtOAc 7:3).
