Citric Acid → (2R)-3-(tert-butoxy)-2-methylpropan-1-ol

A solution of (S)-(+)-methyl 3-hydroxy-2-methylpropionate (1.18 g, 10 mmol) in t-butyl acetate (30 mL) was treated with 70% HClO4 (0.1 mL) and the reaction mixture was left at room temperature in a tightly closed flask for 24 hours. The mixture was then poured into a saturated solution of NaHCO3 and extracted with ethyl ether. The ether was removed in vacuo and the residue was dissolved in THF (50 mL). To the resulting solution was added NaBH4 (925 mg, 25 mmol) and at 55° C. dropwise methanol (10 mL). The reaction was continued at 55° C. for 1 hours, then it was cooled to ambient temperature, acidified with 10% citric acid to pH 5 and extracted with ethyl acetate. The acetate extract was washed with water, brine, dried with MgSO4 and concentrated in vacuo. The residue was chromatographed (silica gel, 2:1 hexane-ethyl acetate) to provide (R)-3-t-butoxy-2-methyl-1-propanol (yield: 1 g, 68%). 1H NMR (300 MHz, CDCl3) δ 0.85 (d, J=7 Hz, 3H), 1.20 (s, 9H), 2.03 (m, 1H), 3.30 (t, J=12 Hz, 1H), 3.53 (dd, J=4.5 Hz, 12 Hz, 1H), 3.70 (m, 2 H); MS (DCI/NH3) m/z 164 (M+NH4)+.

1. extractionextracted with ethyl ether
2. customThe ether was removed in vacuo
3. dissolutionthe residue was dissolved in THF (50 mL)
4. customat 55° C.
5. waitThe reaction was continued at 55° C. for 1 hours
6. extractionextracted with ethyl acetate
7. extractionThe acetate extract
8. washwas washed with water, brine
9. dry with materialdried with MgSO4
10. concentrationconcentrated in vacuo
11. customThe residue was chromatographed (silica gel, 2:1 hexane-ethyl acetate)

ORD record

ord-4bfeabd8532d44f2923e4bbf3d584606

Source dataset

uspto-grants-2006_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07115591B2