Borane → tert-Butyl 2-(hydroxymethyl)morpholine-4-carboxylate

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Reaction Steps

A solution of 4-{[(1,1-dimethylethyl)oxy]carbonyl}-2-morpholinecarboxylic acid (2.0 g, 21.6 mmol) in THF (45 mL) was cooled to 0° C. A solution of borane (39 mL, 39.0 mmol, 1M in THF) was added over 25 min via addition funnel. After warming to RT, the reaction was quenched by dropwise addition of methanol/acetic acid (18 mL, 9:1 v/v). The solvent was removed under reduced pressure and the residue partitioned between ethyl acetate and 1N HCl. The aqueous layer was extracted with ethyl acetate and combined extracts were washed with water, 1N NaOH, water, brine and dried over sodium sulfate. Removal of the solvent under reduced pressure afforded 1.83 g (97%) of the desired material. 1H NMR (400 MHz, CDCl3) δ ppm 1.49 (s, 9H) 2.30 (br d, J=11.37 Hz, 1H) 2.69-2.79 (m, J=9.51, 6.41, 3.28, 3.28 Hz, 1H) 2.84 (ddd, J=13.77, 10.86, 3.16 Hz, 2H) 3.27-3.38 (m, 1H) 3.47 (br s, 1H) 3.63-3.75 (m, 2H) 4.10-4.19 (m, 1H) 4.27 (br s, 1H).

Provenance & Evidence