反应详情

To a solution or tert-butyl 6-bromo-3,3-bis(hydroxymethyl)-2-oxoindoline-1-carboxylate (1.00 g, 2.69 mmol) and 4-methylbenzenesulfonic acid hydrate (0.026 g, 0.134 mmol) in DMF (27 mL) was added 2,2-dimethoxypropane (0.49 mL, 4.03 mmol). The solution was stirred at rt overnight followed by the addition of additional 2,2-dimethoxypropane (0.49 mL, 4.03 mmol) and 4-methylbenzenesulfonic acid hydrate (0.026 g, 0.134 mmol). After stirring at 60° C. for 5 h, the solution was poured into saturated aqueous NaHCO3 and extracted with DCM. The combined organic extracts were purified by column chromatography (eluting with a gradient of 0-30% EtOAc in hexanes) to give tert-butyl 6′-bromo-2,2-dimethyl-2′-oxospiro[[1,3]dioxane-5,3′-indoline]-1′-carboxylate as a white solid. Mass Spectrum (ESI) m/e=434.0 [(M+Na+) (79Br)] and 436.0 [(M+Na+) (81Br)].

1. stirringAfter stirring at 60° C. for 5 h
2. extractionextracted with DCM
3. customThe combined organic extracts were purified by column chromatography (
4. washeluting with a gradient of 0-30% EtOAc in hexanes)