反应详情

Copper (I) triflate (2:1 complex with toluene, 250 mg, 2.4%) and (S,S)-(±)-2,2-isopropylidenebis(4-tert-butyl)-2-oxazoline (205 mg, 3.4%) were stirred in dichloromethane (15 mL) at ambient temperature under N2 atmosphere for 1 hour. A solution of (benzofuran-5-yloxy)(tert-butyl)dimethylsilane (5.0 g, 20.2 mmol) in dichloromethane (85 mL) was added, followed by a slow addition of ethyl diazoethanoate (40 mL, 380 mmol) during a period of 10 hours using a syringe pump. The mixture was concentrated and purified by column chromatography to afford crude compound (7.3 g) which was used for the next step without any further purification.

1. concentrationThe mixture was concentrated
2. custompurified by column chromatography