BOC-D-alanine → 1,1-Dimethylethyl N-((1S)-2-hydroxy-1-methylethyl)carbamate

Temperature

0 °C

As described in literature (Stanfield; et al., JOC., 1981, 46, 4799-800), a solution of Boc-D-Ala-OH (50.0 g, 0.264 mol) in THF (250 mL) was added dropwise to a 0° C. solution of BH3-THF (1.0M in THF, 380 mL, 380 mmol). The mixture was stirred for 2 hours at 0° C. and quenched with a 10% solution of AcOH in MeOH (200 mL). The mixture was concentrated under reduced pressure, diluted with EtOAc (500 mL) and washed with 1N HCl (150 mL). The aqueous was extracted with EtOAc (100 mL) and the combined organic extracts were washed consecutively with H2O (150 mL) and 1N NH4HCO3 (150 mL). The organic layer was dried (Na2SO4), filtered and concentrated in vacuo to give ((S)-2-hydroxy-1-methyl-ethyl)-carbamic acid tert-butyl ester as a colourless oil (43.6 g) that was used in the next step without further purification.

1. customquenched with a 10% solution of AcOH in MeOH (200 mL)
2. concentrationThe mixture was concentrated under reduced pressure
3. additiondiluted with EtOAc (500 mL)
4. washwashed with 1N HCl (150 mL)
5. extractionThe aqueous was extracted with EtOAc (100 mL)
6. washthe combined organic extracts were washed consecutively with H2O (150 mL) and 1N NH4HCO3 (150 mL)
7. dry with materialThe organic layer was dried (Na2SO4)
8. filtrationfiltered
9. concentrationconcentrated in vacuo

ORD record

ord-32240c826343403e839ff75e94f02634

Source dataset

uspto-grants-2009_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07491735B2