prop-2-enyl 2-(5-bromo-2-fluorophenyl)-2-diazoacetate

Conditions: temp:23.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of commercially available rhodium(II) octanoate dimer (Rh2(C7H16CO2)4) ([CAS No. 73482-96-9], 160 mg, 1 mol %) in DCM (60 ml) at 45° C. was added a solution of (5-bromo-2-fluoro-phenyl)-diazo-acetic acid allyl ester (intermediate B4A) (6.0 g, 20 mmol) in DCM (2×20 ml) via syringe pump within 16 h. Continued refluxing for 1 h, cooled to 23° C., washed with 1 M aqueous hydrochloric acid (HCl) and sat. aqueous sodium hydrogencarbonate solution (NaHCO3-sol.), dried organic layer over sodium sulfate. Removal of the solvent in vacuum left a green solid, which was purified by silica gel column chromatography with n-heptane/ethyl acetate to give the title compound as a light green solid (4.6 g, 85%) [cf. Adv. Synth. Catal. 2001, 343, 299, for an enantioselective version of this reaction]. Continued refluxing for 1 h washed with 1 M aqueous hydrochloric acid (HCl) and sat. aqueous sodium hydrogencarbonate solution (NaHCO3-sol.), dried organic layer over sodium sulfate Removal of the solvent in vacuum left a green solid, which was purified by silica gel column chromatography with n-heptane/ethyl acetate

Conditions: temp:23.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) (4.2 ml, 28 mmol) in THF (24 ml) at 23° C. was added a solution of (5-bromo-2-fluoro-phenyl)-acetic acid allyl ester (intermediate B3A) (7.29 g, 27 mmol) and commercially available p-acetamidobenzenesulfonyl azide ([CAS No. 2158-14-7], 6.94 g, 28 mmol) in THF (48 ml) over 1 h. The mixture was stirred for 5 h at 23° C. Then it was quenched with sat. aqueous ammonium chloride solution, diluted with ethyl acetate, and the organic layer was washed with brine and dried over sodium sulfate. Removal of the solvent in vacuum left a yellow oil, which was purified by silica gel column chromatography with hexane/ethyl acetate to give the title compound as a yellow solid (7.344 g, 92%). MS (ISP): m/z=316.1 [(M+NH4)+] and 318.0 [(M+2+NH4)+]. Then it was quenched with sat. aqueous ammonium chloride solution diluted with ethyl acetate the organic layer was washed with brine dried over sodium sulfate Removal of the solvent in vacuum left a yellow oil, which was purified by silica gel column chromatography with hexane/ethyl acetate