Compound 8
(1s,2R,3R,4s,5S,6S)-2,3,4,5,6-pentafluorocyclohexyl trifluoromethanesulfonate
From: All-cis 1,2,3,4,5,6-hexafluorocyclohexane is a facially polarized cyclohexane
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InChIKey UOQSANYUXOHOFI-FAEUDGQSSA-N
Compound data: CIF
Synthetic procedure: See article for the definitive version of this procedure and for full experimental details.
To a suspension of 7 (11.8 mg, 0.06 mmol, 1 eq) in dichloromethane (5 mL) cooled to 0˚C was added triflic anhydride (83 µL, 140 mg, 0.47 mmol, 8 eq) dropwise and the mixture stirred for 20 min. Pyridine (30 µL, 30 mg, 0.03 mmol, 6 eq) was added and the mixture was allowed to warm to RT while stirring for 18 h. The reaction mixture was diluted with saturated aqueous copper (ii) sulfate solution (5 mL) and extracted with ethyl acetate (3 × 10 mL). The combined organic phases were washed with brine (5 mL) dried over MgSO4, filtered and concentrated in vacuo, affording a colourless residue. Purification of the residue by silica gel chromatography, eluting with dichloromethane and methanol (100:0, 99:1), afforded (1s,2R,3R,4s,5S,6S)-2,3,4,5,6-pentafluorocyclohexyl trifluoromethanesulfonate 8 (14.2 mg, 71%) as a colourless solid: 1H NMR (500 MHz, CD2Cl2): δ 5.57 (tt, J = 9.5 Hz, J = 9.5 Hz, 1H, H-1), 5.51–5.34 (m, 2H, H-3 and H-5), 4.82–4.56 (m, 2H, H-2, H-4 and H-6); 19F{1H} NMR (470 MHz, CD2Cl2): δ -74.3 – ‑74.4 (m, 3F, CF3), -208.5 – -208.6 (m, 2F, F-2 and F-6), -213.1 – -213.2 (m, 1F, F-4), -214.9 – -215.0 (m, 2F, F-3 and F-5); HRMS-ESI– (m/z): [M+Cl]– calcd. for C7H6O3F8SCl, 356.9604; found, 356.9609.
