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Benzyl 5-oxotetrahydro-2H-pyran-3-ylcarbamate (4.35 g, 17.45 mmol) and cerium(III) chloride heptahydrate (6.50 g, 17.45 mmol) were dissolved in methanol (100 mL) before cooling to 0° C. Sodium borohydride (0.660 g, 17.45 mmol) was then added slowly. Intense bubbling was observed. The reaction was allowed to stir at 0° C. for 30 min before quenching by addition of acetone (˜3 mL) and stirring at room temperature for 30 additional min. The reaction was then evaporated to dryness. The material was partitioned between DCM and water and the aqueous layer was washed with DCM (5×). The organic layers were combined, dried over sodium sulfate, filtered, and condensed to give impure benzyl 5-hydroxytetrahydro-2H-pyran-3-ylcarbamate (2.5 g, 9.95 mmol, 57.0% yield) as a white solid; 1H NMR (400 MHz, CDCl3) δ ppm 7.28-7.39 (m, 5H), 5.90-6.06 (m, 1H), 5.10 (d, J=4.29 Hz, 2H), 3.59-3.97 (m, 6H), 1.77-2.06 (m, 3H; MS (ESI) m/z 252.1 [M+1]+.

1. customIntense bubbling
2. custombefore quenching by addition of acetone (˜3 mL)
3. stirringstirring at room temperature for 30 additional min
4. customThe reaction was then evaporated to dryness
5. customThe material was partitioned between DCM and water
6. washthe aqueous layer was washed with DCM (5×)
7. dry with materialdried over sodium sulfate
8. filtrationfiltered
9. customcondensed