4-Toluenesulfonyl chloride → (3R,3aS,6R,6aR)-6-Hydroxyhexahydrofuro[3,2-b]furan-3-yl 4-methylbenzenesulfonate
Reaction equation
[CH2:1]1[O:5][C@@H:4]2[C@H:6]([OH:9])[CH2:7][O:8][C@@H:3]2[C@@H:2]1[OH:10].[C:11]1([CH3:21])[CH:16]=[CH:15][C:14]([S:17](Cl)(=[O:19])=[O:18])=[CH:13][CH:12]=1.[OH-].[K+]>C(Cl)(Cl)(Cl)Cl.ClCCl.O>[CH3:21][C:11]1[CH:16]=[CH:15][C:14]([S:17]([O:10][C@@H:2]2[CH2:1][O:5][C@@H:4]3[C@H:6]([OH:9])[CH2:7][O:8][C@H:3]23)(=[O:19])=[O:18])=[CH:13][CH:12]=1Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 3
Conditions
- Temperature
- 0 °C
Procedure
Isomannide (40) (10 g, 68.49 mmol) and p-toluenesulphonyl chloride (6.53 g, 34.25 mmol) were dissolved in a mixture of carbon tetrachloride (50 mL), dichloromethane (5 mL) and water (40 mL). The flask was cooled to 0° C. and a solution of potassium hydroxide (1.92 g, 34.25 mmol) in water (5 mL) added dropwise over 30 minutes with stirring. The resulting biphasic mixture was stirred at 0° C. for 7 hours. Then off-white precipitate was collected by filtration in vacuo then partitioned between dichloromethane (30 mL) and water (10 mL). The organic phase was washed with brine (2×10 mL) then dried (Na2SO4), filtered and reduced in vacuo to leave a colourless solid. Recrystallisation from carbon tetrachloride gave monotosylate (50) as colourless granules (3.92 g, 38%). TLC (Rf=0.11, EtOAc:heptane 1:1); analytical HPLC main peak, Rt=10.692 min; HPLC-MS 318.2, 323.1 [M+Na]+, 623.2 [2M+Na]+; [α]D18 +72.2° (c=5.4, CHCl3); δH (500 MHz, CDCl3) 2.44 (3H, s, CH3), 3.54 (1H, dd, J=9.31 and 7.23 Hz, OCH2CHOH), 3.78 (1H, dd, J=9.18 and 7.59 Hz, OCH2CHOTs), 3.95 (1H, dd, J=9.36 and 6.45 Hz, OCH2CHOH), 4.01 (1H, dd, J=9.33 and 6.64 Hz, OCH2CHOTs), 4.26 (1H, m, CHOH), 4.42 and 4.48 (each 1H, brt, J=5.03 and 5.00 Hz respectively, CHCHCHOH and CHCHCHOTs), 4.90 (1H, dd, J=12.15 and 6.84 Hz, CHOTs), 7.37 (2H, d, J=8.13 Hz, aromatic CH3CCH), 7.82 (2H, d, J=8.20 Hz, aromatic OSO2CCH); δC (125 MHz, CDCl3) 21.69 (CH3), 70.03 (CH2CHOTs), 72.29 (CHOTs), 74.02 (CH2CHOH), 80.00 (CH2CHOH), 81.36 (CHCHOTs), 81.76 (CHCHOH), 128.00 and 129.89 (aromatic CH), 133.04 (CHOSO2C quaternary), 145.26 (CH3C quaternary).
Workup
- stirringThe resulting biphasic mixture was stirred at 0° C. for 7 hours
- filtrationThen off-white precipitate was collected by filtration in vacuo
- customthen partitioned between dichloromethane (30 mL) and water (10 mL)
- washThe organic phase was washed with brine (2×10 mL)
- dry with materialthen dried (Na2SO4)
- filtrationfiltered
- customto leave a colourless solid
- customRecrystallisation from carbon tetrachloride
Sources & evidence
- ORD record
- ord-371d41bc7ad74a3ab95a3dd383c1de01
- Source dataset
- uspto-grants-2013_08
- Patent number
- US08501744B2
Reaction notes
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