[F-].C([N+](CCCC)(CCCC)CCCC)CCC.[Si]([O:26][C@H:27]1[CH2:31][N:30]([C:32]([O:34][C:35]([CH3:38])([CH3:37])[CH3:36])=[O:33])[C@H:29]([CH3:39])[CH2:28]1)(C(C)(C)C)(C)C.CCCCCCC>C1COCC1>[OH:26][CH:27]1[CH2:31][N:30]([C:32]([O:34][C:35]([CH3:38])([CH3:37])[CH3:36])=[O:33])[C@H:29]([CH3:39])[CH2:28]1A solution of tetrabutylammonium fluoride (1M in THF, 28 mL) was added to a solution of (2R,4R)-tert-butyl 4-(tert-butyldimethylsilyloxy)-2-methylpyrrolidine-1-carboxylate (3.87 g, 12.27 mmol) in THF (10 mL). The reaction mixture was stirred at ambient temperature for about 3 hours. The solvent was removed in vacuo and the residue partitioned between EtOAc and water. The aqueous phase was further extracted with EtOAc (3×100 mL). The combined organic extracts were dried over magnesium sulfate, filtered and concentrated in vacuo. Purification by silica gel flash chromatography eluting with 40% EtOAc:heptane yielded (2R)-tert-butyl 4-hydroxy-2-methylpyrrolidine-1-carboxylate (2.3 g, 11.4 mmol) as a colorless oil. 1H NMR (d6 DMSO, 400 MHz) 4.41 (1H, br), 4.00 (1H, br), 3.48 (2H, br), 2.3-2.0 (2H, m), 1.72 (1H, m), 1.46 (9H, s) and 1.22 (3H, d).
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