Tributylborane → 4-[6-(4-Fluorophenyl)spiro[2.4]hept-5-en-5-yl]benzenesulfonamide

HRID 2292984Notes

Reaction equation

HRID 2292984 reaction equation
[F:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[CH2:9][C:10]3([CH2:13][C:14]=2[C:15]2[CH:20]=[CH:19][C:18]([S:21](C)(=[O:23])=[O:22])=[CH:17][CH:16]=2)[CH2:12][CH2:11]3)=[CH:4][CH:3]=1.C[Li].C(B(CCCC)CCCC)CCC.C([O-])(=O)C.[Na+].[NH2:45]OS(O)(=O)=O>C1COCC1.O>[F:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[CH2:9][C:10]3([CH2:12][CH2:11]3)[CH2:13][C:14]=2[C:15]2[CH:20]=[CH:19][C:18]([S:21]([NH2:45])(=[O:23])=[O:22])=[CH:17][CH:16]=2)=[CH:4][CH:3]=1

Participants

8

Reactant 5

HCID 31216TributylboraneHCID 76284hydroxylamine-O-sulfonic acidHCID 517045Sodium AcetateHCID 98517705-(4-Fluorophenyl)-6-(4-methylsulfonylphenyl)spiro[2.4]hept-5-eneHCID 178418348HCID 178418348, compound

Product 1

HCID 99280474-[6-(4-Fluorophenyl)spiro[2.4]hept-5-en-5-yl]benzenesulfonamideYield 28.2%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8028TetrahydrofuranSolvent

Procedure

Under nitrogen, a solution of 90 mg (0.248 mmol) of 5-(4-fluoro phenyl)-6-[4-(methylsulfonyl)phenyl]spiro[2.4]hept-5-ene from step 11 in 1 mL of THF at -78° C. was treated with 0.21 mL (0.27 mmol) of methyllithium (1.3M in ether) over a period of 2 minutes. The reaction was stirred at ambient temperature for 25 minutes, cooled to -78° C., and treated with 0.3 mL (0.3 mmol) of tributylborane (1.0M in THF). The resulting dark brown solution was stirred at ambient temperature for 20 minutes and then at reflux for 16 hour prior to the addition of 350 mg (4.27 mmol) of sodium acetate, 2 mL of water, and 250 mg (2.21 mmol) of hydroxylamine-O-sulfonic acid. The resulting light orange mixture was stirred at ambient temperature for 3 hours and the aqueous phase extracted with ethyl acetate. The combined extracts were washed with water, brine, dried (MgSO4), and concentrated in vacuo. The residue was chromatographed on silica gel to give 24 mg (27%) of 4-[6-(4-fluorophenyl)spiro[2.4]hept-5-en-5-yl]benzenesulfonamide as a colorless solid: mp 131.0°-133.0° C.; NMR (CDCl3) δ 0.68 (s, 4H), 2.90 (s, 3H), 4.81 (s, 2H), 6.92 (t, J=9 Hz, 2H), 7.11 (dd, J=6 and 9 Hz, 2H), 7.27 (d, J=9 Hz, 2H), 7.74 (d, J=9 Hz, 2H). HRMS. Calc'd for C19H18FNO2S: 344.1121. Found: 344.1122. Anal. Calc'd for [C19H18FNO2S+0.1 CH3CO2 CH2CH3 ]: C, 66.16; H, 3.98; S, 9.11. Found: C, 65.86; H, 5.52; N, 3.92; S, 9.57.

Workup

  1. temperaturecooled to -78° C.
  2. stirringThe resulting dark brown solution was stirred at ambient temperature for 20 minutes
  3. temperatureat reflux for 16 hour
  4. stirringThe resulting light orange mixture was stirred at ambient temperature for 3 hours
  5. extractionthe aqueous phase extracted with ethyl acetate
  6. washThe combined extracts were washed with water, brine
  7. dry with materialdried (MgSO4)
  8. concentrationconcentrated in vacuo
  9. customThe residue was chromatographed on silica gel

Sources & evidence

ORD record
ord-4fb3e72e48474794ae5c6181159a5966
Source dataset
uspto-grants-1997_11
Patent number
US05684195

Reaction notes

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