[OH:1][CH2:2][CH2:3][C:4]([O:6][CH3:7])=[O:5].[O:8]1[CH:13]=[CH:12][CH2:11][CH2:10][CH2:9]1>ClCCl.C1(C)C=CC(S([O-])(=O)=O)=CC=1.[NH+]1C=CC=CC=1>[O:8]1[CH2:13][CH2:12][CH2:11][CH2:10][CH:9]1[O:1][CH2:2][CH2:3][C:4]([O:6][CH3:7])=[O:5]Pyridinium p-toluenesulfonate (7.65 g, 30.45 mmol) was added to a clear solution of methyl 3-hydroxypropanoate (63.4 g, 609.00 mmol) and 3,4-dihydro-2H-pyran (78 mL, 852.60 mmol) in dichloromethane (650 mL) at room temperature under nitrogen to give a cloudy solution. This was allowed to stir at room temperature overnight. The reaction mixture was washed with water (250 mL) and brine (250 mL) before drying (MgSO4) and evaporating to an oil. This crude product was purified by flash silica chromatography, elution gradient 15 to 30% EtOAc in heptane. Pure fractions were evaporated to dryness to afford methyl 3-(tetrahydro-2H-pyran-2-yloxy)propanoate (67.7 g, 59.0%) as a colourless oil: 1H NMR Spectrum: (CDCl3) 1.47 (4H, dddd), 1.55-1.84 (2H, m), 2.55 (2H, t), 3.33-3.53 (1H, m), 3.53-3.7 (4H, m), 3.78 (1H, ddd), 3.93 (1H, dt), 4.42-4.72 (1H, m); Mass Spectrum [MH]+=189.
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