1,3-Dibromopropane → Methyl 5-bromo-2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pentanoate

Participants

Reaction Conditions

Reaction Steps

Sodium hydride (0.153 g, 3.83 mmol) was added in one portion to methyl 2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acetate (Intermediate 2-7; 1.08 g, 3.48 mmol) in DMF (20 mL) cooled to 0° C. under nitrogen. The resulting solution was stirred at 0° C. for 10 minutes. 1,3-Dibromopropane (0.392 mL, 3.83 mmol) was added to the reaction and was stirred at 0° C. for 5 minutes. Sodium hydride (0.153 g, 3.83 mmol) was added in one portion to the reaction and stir at 0° C. for 1 hour. The reaction mixture was quenched with saturated NH4Cl (50 mL). The reaction mixture was diluted with EtOAc (75 mL), and washed sequentially with water (4×50 mL) and saturated brine (50 mL). dried over MgSO4 The organic layer was evaporated to afford crude product. The crude product was purified by flash silica chromatography, elution gradient 0 to 30% EtOAc in isohexane. Pure fractions were evaporated to dryness to afford methyl 5-bromo-2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pentanoate (0.362 g, 24.12%) as a colourless gum.

Provenance & Evidence