Carbon tetrabromide → Benzyl ((2R,3S)-2-(3,3-dibromoallyl)-1-(2,4-dimethoxybenzyl)-4-oxoazetidin-3-yl)(4-methoxybenzyl)carbamate

Participants

Reaction Steps

To a solution of PPh3 (302.4 mg, 1.15 mmol) in DCM (1 mL) at 0° C. was added CBr4 (192 mg, 0.58 mmol). After 10 min, a solution of benzyl ((3S,4R)-1-(2,4-dimethoxybenzyl)-2-oxo-4-(2-oxoethyl)azetidin-3-yl)(4-methoxybenzyl)carbamate (152.7 mg, 0.29 mmol) in DCM (800 μL) was added dropwise followed by DCM (800 μL) wash. After 20 min, the reaction mixture was diluted with DCM and water, and the layers were separated. The aqueous layer was extracted with DCM (2×). Combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated in vacuo. The residue was purified via silica gel chromatography (0-40% EtOAc-Hept) to afford the title compound (162 mg, 82%). LCMS: Rt=1.2 min, m/z=689.1 (M+1) Method 2m_acidic.

Provenance & Evidence