Methyl iodide → tert-Butyl 3-cyano-3-methylazetidine-1-carboxylate

Temperature

-76 °C

In a 100 mL 2-neck round-bottomed flask, tert-butyl 3-cyanoazetidine-1-carboxylate (1.5 g, 8.2 mmol) was dissolved in THF (30 mL). The colorless solution was cooled to −76° C. and lithium bis(trimethylsilyl)amide (1.0M solution in THF, 9.0 mL, 9.0 mmol) was added dropwise over 25 min. The yellow solution was stirred at −76° C. for 30 min then iodomethane (0.78 mL, 12.5 mmol) was slowly added. The reaction mixture was stirred at −76° C. for 30 min and then warmed to room temperature over 1 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: 0-30% EtOAc). All fractions containing product were combined and concentrated to afford 1.44 g (89%) of 3-cyano-3-methyl-azetidine-1-carboxylic acid tert-butyl ester as a yellow solid.

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

ORD record

ord-bd6ee162e6054dca8d6bed578e0cb265

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08518945B2