Iodine → 3,4-Di-O-benzyl-2-O-levulinoyl-alpha-L-rhamnopyranose

HRID 1644786Notes

Reaction equation

HRID 1644786 reaction equation
[CH2:1]([O:8][C@@H:9]1[C@@H:18]([O:19][CH2:20][C:21]2[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=2)[C@H:17]([CH3:27])[O:16][C@@H:11]([O:12]CC=C)[C@@H:10]1[O:28][C:29](=[O:35])[CH2:30][CH2:31][C:32]([CH3:34])=[O:33])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.II>C1COCC1.C1COCC1.O>[CH2:1]([O:8][C@@H:9]1[C@@H:18]([O:19][CH2:20][C:21]2[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=2)[C@H:17]([CH3:27])[O:16][C@@H:11]([OH:12])[C@@H:10]1[O:28][C:29](=[O:35])[CH2:30][CH2:31][C:32]([CH3:34])=[O:33])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

5

Reactant 2

HCID 807IodineHCID 25157484Allyl 3,4-di-O-benzyl-2-O-levulinoyl-alpha-L-rhamnopyranoside

Product 1

HCID 251574853,4-Di-O-benzyl-2-O-levulinoyl-alpha-L-rhamnopyranoseYield 94.2%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent2×HCID 21881883Oxolane--water (1/1)Solvent

Procedure

1,5-Cyclooctadiene-bis(methyldiphenylphosphine)iridium hexafluorophosphate (25 mg, 20 μmol) was dissolved THF and the resulting red solution was degassed in an argon stream. Hydrogen was then bubbled through the solution, causing the colour to change to yellow. The solution was then degassed again in an argon stream. A solution of 210 (1.4 g, 3.12 mmol) in THF was degassed and added. The mixture was stirred at rt overnight, then concentrated to dryness. The residue was dissolved in a solution of I2 (1.37 g, 5.4 mmol) in 30 mL of THF/H2O (15:4). The mixture was stirred at rt for 1 h, and THF was evaporated. The resulting suspension was taken up in DCM, washed twice with water, satd aq NaHSO3, water, satd aq NaHCO3, water and satd aq NaCl, successively. The organic layer was dried and concentrated. The residue was eluted from a column of silica gel with 7:3 to 6:4 Cyclohexane-EtOAc to give the corresponding hemiacetal 211 (1.3 g, 93%). 1H NMR: δ 7.40-7.30 (m, 10H, Ph), 5.40 (dq, 1H, J1,2=1.8, J2,3=3.4 Hz, H-2), 4.93 (d, 1H, J=10.8 Hz, CH2Ph), 4.78 (d, 1H, J1,2=1.6 Hz, H-1), 4.78 (d, 1H, J=11.2 Hz, CH2Ph), 4.63 (d, 1H, CH2Ph), 4.51 (d, 1H, CH2Ph), 3.99 (m, 1H, J3,4=9.5 Hz, H-3), 3.78 (dq, 1H, J4,5=9.5, J5,6=6.2 Hz, H-5), 3.43 (pt, 1H, H-4), 2.80 (m, 4H, Lev), 2.19 (s, 3H, Ac), 1.37 (d, 3H, H-6). Anal. Calcd for C28H34O7: C, 67.86; H, 6.83. Found: C, 67.94; H, 6.87.

Workup

  1. customthe resulting red solution was degassed in an argon stream
  2. customHydrogen was then bubbled through the solution
  3. customThe solution was then degassed again in an argon stream
  4. additionadded
  5. concentrationconcentrated to dryness
  6. stirringThe mixture was stirred at rt for 1 h
  7. customTHF was evaporated
  8. washwashed twice with water
  9. customThe organic layer was dried
  10. concentrationconcentrated
  11. washThe residue was eluted from a column of silica gel with 7:3 to 6:4 Cyclohexane-EtOAc

Sources & evidence

ORD record
ord-b57987557f1543c3b885a7b5ddb43294
Source dataset
uspto-grants-2012_02
Patent number
US08124380B2

Reaction notes

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