1,2-Dibromoethane → Methyl 1-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)cyclopropane-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

Lithium bis(trimethylsilyl)amide (7.08 mL, 7.08 mmol) was added dropwise to methyl 2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)acetate (1 g, 3.22 mmol) in THF (20 mL) cooled to 0° C. under nitrogen. The resulting solution was stirred at 0° C. for 30 minutes and then 1,2-dibromoethane (0.305 mL, 3.54 mmol) was added to the reaction and was stirred at 0° C. for 5 minutes. The reaction mixture was quenched with saturated NH4Cl (50 mL) and was diluted with EtOAc (75 mL). The organic layer was separated and re-extracted with EtOAc (75 mL). The combined organics were washed with saturated brine (50 mL), dried (MgSO4), filtered and concentrated 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 1-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)cyclopropanecarboxylate (0.182 g, 16.79%) as a colourless gum.

Provenance & Evidence