1,1,2,2,3,3,4,4,4-Nonafluorobutane-1-sulphonic anhydride

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

Procedure: 1,1,2,2,3,3,4,4,4-Nonafluorobutanesulfonic anhydride (0.75 g, 0.40 mL, 1.3 mmol) was added dropwise to a suspension of 9-benzenesulfonyl-5-hydroxy-3-(1-methyl-1H-pyrazol-4-yl)-9H-dipyrido[2,3-b;4′,3′-d]pyrrole-6-carbonitrile (106 mg, 0.25 mmol) in pyridine (0.7 mL, 8.0 mmol) and dry DCM (7 mL) at 0° C. The reaction mixture was then allowed to warm to ambient temperature and stirred for 4 h. The reaction mixture was treated with 1N hydrochloric acid (6 mL) and the phases were separated. The aqueous phase was extracted with DCM (2×10 mL), the combined organic phase was dried over anhydrous magnesium sulfate and concentrated in vacuo. The resultant residue was purified by chromatography (silica, 2 g column, Si-SPE, gradient of DCM/EtOAc) and further trituration with pentane (2 mL) to afford the title compound as a white solid (150 mg, 84%). 1H NMR (CDCl3, 400 MHz): 9.95 (s, 1H), 8.99 (d, J=2.1 Hz, 1H), 8.74 (d, J=2.1 Hz, 1H), 8.35-8.32 (m, 2H), 7.86 (d, J=0.8 Hz, 1H), 7.74-7.68 (m, 2H), 7.61-7.56 (m, 2H), 4.04 (s, 3H). LCMS (Method G): RT=4.80 min, M+H+=713. the phases were separated The aqueous phase was extracted with DCM (2×10 mL) the combined organic phase was dried over anhydrous magnesium sulfate concentrated in vacuo The resultant residue was purified by chromatography (silica, 2 g column, Si-SPE, gradient of DCM/EtOAc) and further trituration with pentane (2 mL)

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

Procedure: The production of tert-butyl nonafluorobutanesulphonyloxypropionate was effected with nonafluorobutanesulphonic anhydride as in example 1 with a yield of 82% (ee>99%).