Phosphorus oxybromide → HCID 22595770, compound

Participants

Reaction Steps

Alternatively, the above reaction can be run using the following procedure: POBr3 (39.2 g, 137 mmol, 2 equiv) was added to a stirred solution of 3 (20 g, 68 mmol) in dichloroethane (150 mL). The reaction was heated to reflux for 8 h. After cooling to rt, the reaction was quenched by the slow addition of ice. (Here I let it stir over the weekend—but not necessary). The organic layer was separated and the aqueous layer was extracted with CHCl3 (2×100 mL). The combined organic layer was washed with NaHCO3 (1×150 mL), H2O (1×150 mL), NaHSO3 (1×150 mL), H2O (1×150 mL), brine (1×150 mL) and dried over MgSO4. The residue was recrystallized from EtOH to afford the desired product, 16.12 g (67%). An additional 1.87 g was obtained by column chromatography of the concentrated filtrate (SiO2, 5% ethyl acetate-hexane). Total yield 17.99 g (74%).

Provenance & Evidence