Allyl bromide → (2S,3R)-3-Allyl-1-(tert-butyl-dimethyl-silanyl)-4-oxo-azetidine-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-1-(tert-butyldimethylsilyl)-4-oxoazetidine-2-carboxylic acid (4) (2.00 g, 8.73 mmol.) in anhydrous THF (20 mL) at −78° C. was added 1.0 M solution of LiHMDS (20 ml, 20.1 mmol, 2.3 eq.) in THF. After the solution was stirred for 30 min. at −78° C., it was warmed to 0° C. for 10 min. The solution was recooled to −78° C. and allyl bromide (1.28 g, 10.5 mmol, 1.2 eq.) was added slowly. The reaction solution was stirred at −78° C. for 1 h, then warmed up to room temperature and stirred for another hour. The reaction mixture was quenched with aqueous 10% KHSO4 solution (30 ml) and extracted with ethyl acetate (40 mL×3). The combined organic layers were washed with brine twice and dried over Na2SO4. After removal of solvent, compound 57 was obtained as crystalline solid (2.0 g, 85%); 78% purity by LCMS, 1HNMR (300 MHz, CDCl3): 0.12 (s, 3H), 0.30 (s, 3H), 0.95 (s, 9H), 2.55 (m, 2H), 3.41 (m, 1H), 3.80 (d, J=2.61 Hz, 1H), 5.16 (m, 2H), 5.72 (m, 1H). Anal. C13H23NO3Si, Mol. Wt.: 269.41. Found: ESI-MS: 270.0 (M+H)+.

Provenance & Evidence