反应详情

To a solution of commercially available rhodium(II) octanoate dimer (Rh2(C7H16CO2)4) CAS-no. [73482-96-9] (440 mg, 565 μmol, Eq: 0.00941) in dichloromethane (180 ml) at 50° C. was added a solution of allyl 2-diazo-2-(3-nitrophenyl)acetate (intermediate B4a) (14.85 g, 60.1 mmol, Eq: 1.00) in dichloromethane (38 ml) via syringe pump within 18 h. Refluxing was continued for 30 min, the solvent was evaporated and the crude material was purified by flash chromatography (silica gel, 70 g, 0% to 100% EtOAc in heptane) to give (1SR,5RS)-1-(3-nitrophenyl)-3-oxabicyclo[3.1.0]hexan-2-one (12 g, 54.7 mmol, 91.1% yield) as a light brown solid. [cf. Adv. Synth. Catal. 2001, 343, 299 for an enantioselective version of this reaction]. MS (ISP): m/z=237.1 [(M+NH4)+].

1. temperatureRefluxing
2. customthe solvent was evaporated
3. customthe crude material was purified by flash chromatography (silica gel, 70 g, 0% to 100% EtOAc in heptane)