反应详情

A solution of methyl 2-diazo-3-(4-hydroxyphenyl)propanoate (cf Tetrahedron Lett., 1971, 4495) (8.58 g) in methanol (120 mL) was added over 10 minutes to a mixture of rhodium (II) acetate dimer (0.18 g) in methanol (50 mL) at room temperature under a nitrogen atmosphere. The resulting mixture was heated at reflux for 5 hrs, allowed to stand at room temperature for 15 hrs, then concentrated in vacuo. The residue was dissolved in ethyl acetate (500 mL), washed with water (3×300 mL) and brine (500 mL), dried (MgSO4) and evaporated. The resulting gum was chromatographed on silica gel with a gradient of 4% ethyl acetate to 6% ethyl acetate in dichloromethane as eluent to afford the title compound. mp 61°-3° C.

1. temperatureThe resulting mixture was heated
2. temperatureat reflux for 5 hrs
3. concentrationconcentrated in vacuo
4. dissolutionThe residue was dissolved in ethyl acetate (500 mL)
5. washwashed with water (3×300 mL) and brine (500 mL)
6. dry with materialdried (MgSO4)
7. customevaporated
8. customThe resulting gum was chromatographed on silica gel with a gradient of 4% ethyl acetate to 6% ethyl acetate in dichloromethane as eluent