2-Butene, 1-bromo-3-methyl- → 1-tert-Butyl 2-methyl 2-(3-methylbut-2-en-1-yl)pyrrolidine-1,2-dicarboxylate

Temperature

-78 °C

1-tert-Butyl 2-methyl (2S)-pyrrolidine-1,2-dicarboxylate (2.29 g, 0.00999 mol) was dissolved in anhydrous THF (30 mL) and the solution was cooled to −78° C. prior to the drop-wise addition of 1.0 M of lithium hexamethyldisilazide in THF (16 mL) over 15 min. After stirring for 1 h, 1-bromo-3-methylbut-2-ene (1.6 mL, 0.014 mol) was added and the resultant solution was stirred for 5 hours at −78° C. The reaction was quenched by the drop-wise addition of saturated NH4Cl (15 mL). After gradually warming to room temperature (RT), the reaction mixture was diluted with EtOAc (100 mL) and water (10 mL). The organic layer was washed with water (15 mL) and the combined aqueous phases were extracted with EtOAc several times. The combined organic phases were washed with brine, dried (Na2SO4), and concentrated in vacuo to afford the desired product, which was used in the subsequent step without further purification. LC-MS: 198.2 (M−Boc+2H)+ and 320.2 (M+Na)+.

1. customThe reaction was quenched by the drop-wise addition of saturated NH4Cl (15 mL)
2. temperatureAfter gradually warming to room temperature (RT)
3. additionthe reaction mixture was diluted with EtOAc (100 mL) and water (10 mL)
4. washThe organic layer was washed with water (15 mL)
5. extractionthe combined aqueous phases were extracted with EtOAc several times
6. washThe combined organic phases were washed with brine
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated in vacuo

ORD record

ord-3726d43fff0a4ea2a02c73957aadf83d

Source dataset

uspto-grants-2011_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07998959B2