Potassium bis(trimethylsilyl)amide → tert-butyl N-(3-methylidenecyclobutyl)carbamate

Temperature

-78 °C

To a three necked flask equipped with additional funnel which was cooled to −78° C. was added a solution of methyl(triphenyl)phosphonium bromide (43 g, 121 mmol) in anhydrous tetrahydrofuran (200 mL) under nitrogen protection. 1 M KHMDS in tetrahydrofuran (105 mL, 105 mmol) was then introduced dropwise over 40 minutes while the internal temperature was kept below −60° C. After addition, the mixture was stirred at −78° C. for 15 minutes. Then a solution of tert-butyl(3-oxocyclobutyl)carbamate (14 g, 81 mmol) in 100 mL of tetrahydrofuran was added slowly while the internal temperature was kept below −60° C. The resulting mixture was then warmed naturally to room temperature and stirred overnight. The resulting reaction mixture was diluted with EtOAc, and then washed with saturated aqueous solution of ammonium chloride and brine, then dried over anhydrous Na2SO4 and then concentrated in vacuo. The residue was purified by flash chromatography (EA:PE=1:10 to 1:2) to afford tert-butyl(3-methylidenecyclobutyl)carbamate (7.5 g).

1. customTo a three necked flask equipped with additional funnel which
2. customwas kept below −60° C
3. additionAfter addition
4. customwas kept below −60° C
5. temperatureThe resulting mixture was then warmed naturally to room temperature
6. stirringstirred overnight
7. customThe resulting reaction mixture
8. washwashed with saturated aqueous solution of ammonium chloride and brine
9. dry with materialdried over anhydrous Na2SO4
10. concentrationconcentrated in vacuo
11. customThe residue was purified by flash chromatography (EA:PE=1:10 to 1:2)

ORD record

ord-79d6ecb5ec1948d98d86e1f8fd1a1cca

Source dataset

uspto-grants-2015_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09206191B2