Benzyl Bromide → Methyl (2S,3S)-2-Benzyl-3-Hydroxybutyrate

Temperature

-40 °C

Subsequently, in a 50 ml flask were charged 3.3 g (30.0 mmol) of diisopropylamine and 10 ml of tetrahydrofuran, and 16.6 ml (24.9 mmol) of n-butyllithium 1.5M hexane solution was added thereto dropwise on an ice bath in a nitrogen stream. The mixture was then stirred for 1 hour at that temperature. The reaction mixture was further cooled to −40° C., and 1.40 g (11.9 mmol) of methyl (S)-3-hydroxybutyrate prepared as above was added thereto dropwise. After the mixture was stirred for 0.5 hour, 3.00 g (17.5 mmol) of benzyl bromide dissolved in 6 ml of hexamethylphosphoramide was added thereto dropwise at −10° C. or lower temperature. After the addition, the temperature was heated up to 0° C., and the mixture was stirred for 15 min. The resulting mixture was then poured into an ice water, and was extracted with ethyl acetate. The ethyl acetate layer was concentrated to give 3.90 g of a crude product. The crude product was subjected to column chromatography (hexane/ethyl acetate=4/1 by volume) to obtain 1.50 g (61%) of the title compound (anti/syn=98/2).

1. additionwas added
2. additionas above was added
3. stirringAfter the mixture was stirred for 0.5 hour
4. additionwas added
5. customdropwise at −10° C.
6. additionAfter the addition
7. temperaturethe temperature was heated up to 0° C.
8. stirringthe mixture was stirred for 15 min
9. extractionwas extracted with ethyl acetate
10. concentrationThe ethyl acetate layer was concentrated
11. customto give 3.90 g of a crude product

ORD record

ord-66abbe74c35b49749bb938c376d7091e

Source dataset

uspto-grants-2002_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06403804B1