反应详情

Diisopropyl azodicarboxylate (6.45 mL) is added dropwise to a stirred, cooled (0° C.) solution of triphenylphosphine (8.6 g) in dry tetrahydrofuran (60 mL). After a further 30 minutes, a solution of 2′-hydroxy-4′-(pyridin-3-ylmethoxy)benzophenone (5 g) and tert-butyl 4-hydroxy-4-(2-methylphenyl)butanoate, thought to be the (S)-enantiomer, (5.13 g) in dry tetrahydrofuran (60 mL) is added dropwise over 25 minutes and stirring continued for a further 3 hours at °C. The reaction is allowed to warm to ambient temperature overnight before being concentrated under vacuo. The resultant oil is purified by flash chromatography on silica eluting with a mixture of dichloromethane and ethyl acetate (9:1 v/v). Fractions homogeneous in the required product are combined and concentrated under reduced pressure to give t-butyl 4-[2-benzoyl-5-(pyridin-3-ylmethoxy)phenoxy]-4-(2-methylphenyl)butanoate, thought to be the (R)-enantiomer, as a colourless oil (8.66 g).

1. additionis added dropwise over 25 minutes
2. waitcontinued for a further 3 hours at °C
3. concentrationbefore being concentrated under vacuo
4. customThe resultant oil is purified by flash chromatography on silica eluting with a mixture of dichloromethane and ethyl acetate (9:1 v/v)
5. concentrationconcentrated under reduced pressure