N,N,N',N'-Tetramethylethylenediamine → HCID 123368749, compound

Participants

Reaction Steps

s-BuLi (35 mL, 1.3M in cyclohexane) was added to TMEDA (6.6 mL) at −78° C. drop wise within 30 min, 20 mL of THF was added to keep stirring. After 20 min, 6-methoxy-2,2-dimethyl-2,3-dihydrobenzofuran (5.4 g, 30.3 mmol) in THF (30 mL) was added into the lithium solution slowly. The solution was stirred at −78° C. for 1.5 h and trimethyl borate (18 mL) was added. The mixture was warmed to room temperature and stirred at room temperature overnight. The solution was acidified to pH=5-6 and extracted with ethyl acetate. The organic layer was concentrated and the resulted residue was purified on column chromatography (silica gel, dichloromethane/petroleum ether=3/1) to give the crude product, which was sonicated with petroleum ether. The white precipitate was filtered and dried to give 6-methoxy-2,2-dimethyl-2,3-dihydrobenzofuran-7-ylboronic acid (3.55 g, 53%) as a white solid.

Provenance & Evidence