Isopropyl chloroformate → tert-Butyl 3-(hydroxymethyl)azetidine-1-carboxylate

Temperature

0 °C

A solution of 1-Boc-azetidine-3-carboxylic acid (1.6 g) and Et3N (2 ml) in anhydrous THF (60 ml) was cooled to 0° C. Isopropyl chloroformate (1.3 g) was added via a syringe slowly; forming a white precipitate almost immediately. The reaction was stirred for 1 h at 0° C. and the precipitate was filtered out. The filtrate was cooled to 0° C. again and aqueous NaBH4 solution (900 mg, 5 ml) was added via pipette and stirred for 1 h. The reaction was quenched with NaHCO3 solution (50 mL) and the product was extracted with EtOAc (200 mL). The organic phase was washed with brine (50 mL), dried over Na2SO4 and concentrated in vacuo. The residue was dissolved in EtOAc and passed through a short silica gel pad. Concentrating the filtrate in vacuo provided the compound as a light yellow oil.

1. customforming a white precipitate almost immediately
2. filtrationthe precipitate was filtered out
3. temperatureThe filtrate was cooled to 0° C. again
4. additionaqueous NaBH4 solution (900 mg, 5 ml) was added via pipette
5. stirringstirred for 1 h
6. customThe reaction was quenched with NaHCO3 solution (50 mL)
7. extractionthe product was extracted with EtOAc (200 mL)
8. washThe organic phase was washed with brine (50 mL)
9. dry with materialdried over Na2SO4
10. concentrationconcentrated in vacuo
11. dissolutionThe residue was dissolved in EtOAc
12. concentrationConcentrating the filtrate in vacuo

ORD record

ord-9d35cd0c33ec4988b00771202572c11d

Source dataset

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08642624B2