Lithium Hexamethyldisilazide → Methyl 1-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)cyclobutanecarboxylate

Participants

Reaction Conditions

Reaction Steps

Lithium bis(trimethylsilyl)amide (0.872 mL, 0.87 mmol) was added dropwise to methyl 5-bromo-2-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pentanoate (Intermediate 7-3; 342 mg, 0.79 mmol) in THF (10 mL) cooled to 0° C. under nitrogen the reaction and was stirred at 0° C. for 12 hours. 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)cyclobutanecarboxylate (273 mg, 98%) as a colourless gum.

Provenance & Evidence