Iodoethane → Tert-butyl 3-cyano-3-ethylazetidine-1-carboxylate

In a 100 mL 2-neck round-bottomed flask, tert-butyl 3-cyanoazetidine-1-carboxylate (0.80 g, 4.4 mmol) was dissolved in THF (16 mL). The colorless solution was cooled to −76° C. and lithium bis(trimethylsilyl)amide (1.0M solution in THF, 4.8 mL, 4.8 mmol) was added dropwise over 20 min. The yellow solution was stirred at −76° C. for 30 min then iodoethane (0.50 mL, 6.2 mmol) was slowly added. The reaction mixture was stirred at −76° C. for 30 min and then warmed to room temperature and stirred for 3 h. The reaction mixture was quenched with 10 mL of saturated NH4Cl and diluted with 10 mL of water then extracted with ˜100 ml EtOAc (2×). The combined organic layers were washed with ˜10 mL water and ˜10 mL brine then dried over sodium sulfate, filtered and concentrated. The residue was chromatographed over 40 g silica gel with EtOAc/hexanes, (gradient: 0-20% EtOAc). All fractions containing product were combined and concentrated to afford 0.84 g (91%) of 3-cyano-3-ethyl-azetidine-1-carboxylic acid tert-butyl ester as a light yellow oil.

1. stirringThe reaction mixture was stirred at −76° C. for 30 min
2. temperaturewarmed to room temperature
3. stirringstirred for 3 h
4. customThe reaction mixture was quenched with 10 mL of saturated NH4Cl
5. additiondiluted with 10 mL of water
6. extractionthen extracted with ˜100 ml EtOAc (2×)
7. washThe combined organic layers were washed with ˜10 mL water and ˜10 mL brine
8. dry with materialthen dried over sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated
11. customThe residue was chromatographed over 40 g silica gel with EtOAc/hexanes, (gradient: 0-20% EtOAc)
12. additionAll fractions containing product
13. concentrationconcentrated

ORD-Eintrag

ord-23e0077ee3534c7082148648c2c4f162

Quelldatensatz

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08518945B2