Hexane → 3-Boc-2,2-dimethyloxazolidine-4-carboxaldehyde, (R)-(+)-

Temperatur

-78 °C

To a cooled solution of 3-tert-butyl 4-methyl (4R)-2,2-dimethyl-1,3-oxazolidine-3,4-dicarboxylate (16.5 g, 63.6 mmol) in dry dichloromethane (300 mL) at −78° C., was added a cooled solution of 1.0 M diisobutylaluminium hydride in hexane (127.6 mL, 127.2 mmol) under argon. The rate of addition was adjusted so as to keep the internal temperature below −65° C. and take about 1 hour to complete. The reaction mixture was stirred for an additional 2 hours at −78° C. under argon. The reaction was quenched by slowly adding 60 mL of cold methanol (−78° C.) so as to keep the internal temperature below −65° C. The resulting mixture was extracted with ethyl acetate. The organic layer was washed with brine, dried over sodium sulfate, concentrated under reduced pressure. The residue was distilled at 0.7 mbar to give tert-butyl (4R)-4-formyl-2,2-dimethyl-1,3-oxazolidine-3-carboxylate (10 g, 68.5%) as colorless liquid.

1. additionThe rate of addition
2. customthe internal temperature below −65° C.
3. customThe reaction was quenched
4. additionby slowly adding 60 mL of cold methanol (−78° C.) so as
5. customthe internal temperature below −65° C
6. extractionThe resulting mixture was extracted with ethyl acetate
7. washThe organic layer was washed with brine
8. dry with materialdried over sodium sulfate
9. concentrationconcentrated under reduced pressure
10. distillationThe residue was distilled at 0.7 mbar

ORD-Eintrag

ord-1935fba6cfd943b6998f07dbc66f1b4f

Quelldatensatz

uspto-grants-2014_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08871756B2