Boron tribromide → 648904-56-7

Participants

Reaction Conditions

Reaction Steps

Dissolve the product of Example 2 (6.45 g, 11.4 mmol) in dichloromethane (200 mL) and cool to 3° C. in an ice bath. Treat this solution with neat BBr3 (5.4 mL, 57 mmol), dropwise over 5 minutes, and stir for 3 hours at 0 to 10° C. Slowly pour the reaction mixture into a 1-liter separatory funnel containing saturated aqueous NaHCO3 (300 mL) and ice. Dilute the two-phase mixture with a solution of 7.5% MeOH in ethyl acetate (EtOAc, 400 mL) and brine (100 mL). Separate the layers and back extract the aqueous layer with 5% MeOH in EtOAc (2×150 mL). Wash the combined organic layers with brine (100 mL), dry (Na2SO4), filter and evaporate to obtain 5.3 g of crude product. Chromatograph the residue on a SiO2 column eluting the material with methanol in dichloromethane (2.5 to 12%) to give 4.99 grams of the title compound (85%). Dry at 45° C. (<2 mm of Hg) for 18 hours: mass spectrum (ion spray): m/z=518.3 (M+H).

Provenance & Evidence