To 195 mg (0.45 mmol) 3-(2-iodo-phenylcarbamoyl)-azetidine-1-carboxylic acid benzyl ester in 4.5 mL DME in a sealed tube under nitrogen were added 291 mg (0.89 mmol) Cs2CO3, 8.1 mg (44.6 μmol) 1,10-phenanthroline, 4.3 mg (22.3 μmol) CuI, and the mixture was heated at 90° C. for 16 hours. After cooling to room temperature, 5 mL H2O was added followed by 4 drops 1 M HCl, 5 mL NaHCO3 and the mixture was extracted with DCM (3×10 mL). The organic layers were combined and dried with Na2SO4. After filtration and evaporation of the solvent the product was purified by preparative HPLC.
