Et3N (5 mL) was added into a solution of tert-butyl hexahydropyrrolo[3,4-c]pyrrole-2(1H)-carboxylate (1 g) and 5-chloro-1-phenyl-1H-tetrazole (1 g) in dioxane (50 mL). The mixture was heated to 115° C. for 24 hours. The reaction was quenched with water (50 mL). The aqueous layer was extracted with EtOAc (3×50 mL). The combined organic phase was dried over MgSO4 and concentrated to give a residue which was purified by silica gel chromatography to give tert-butyl 5-(1-phenyl-1H-tetrazol-5-yl)hexahydropyrrolo[3,4-c]pyrrole-2(1H)-carboxylate.
