反应详情

A solution of triphenylphosphine(5.48 g) in dry THF (35 mL) is treated with diisopropyl azodicarboxylate (4.23 g) at 0-5° C. and stirred for 15 minutes. The suspension is treated dropwise with a solution of methyl 4-benzyloxy-2-hydroxybenzoate (2.7 g) and 1-o-tolylethanol (1.42 g) in dry THF (35 mL) during 25 minutes at 0-5° C. and then stirred at 0-5° C. for 1 hour and at 25° C. for 24 hours. The mixture is evaporated and the residual gum purified by flash chromatography on silica, eluting with dichloromethane. Fractions homogeneous in the required product are combined and evaporated to yield methyl 4-benzyloxy-2-(1-o-tolyiethoxy)benzoate as a colourless oil (2.83 g, 72%). 1H NMR (CDCl3) 1.6(3H,d), 2.4(3H,s), 3.9(3H,s), 4.9(2H,s), 5.5(1H,q), 6.3(1H,s), 6.5(1H,d), 7.1-7.6(9H,m), 7.8(1H,d).

1. stirringstirred at 0-5° C. for 1 hour and at 25° C. for 24 hours
2. customThe mixture is evaporated
3. customthe residual gum purified by flash chromatography on silica
4. washeluting with dichloromethane
5. customevaporated