Convenient procedure for the synthesis of 2-monoalkylated indol-3-ones
摘要:
2-Alkyl-1,2-dihydroindol-3-ones are prepared from readily available 1-acetyl-2-methoxy-1,2-dihydroindol-3-one by alkylation, reduction with sodium borohydride, and demethoxylation of the resulting 3-hydroxy-2-methoxy-2,3-dihydroindoles with Lewis acids. The stereochemistry of the reduction is also described.
Treatment of 2,3-dihydro-1H-indol-3-ones with allyl alcohols in the presence of camphorsulfonic acid and magnesium sulfate at 130 °C gave, via condensation and a Claisen rearrangement, 2-allyl-2,3-dihydro-1H-indol-3-ones in good yields. The stereochemistry of the products was determined by NOE experiments.
2,3- 二氢-1H-吲哚-3-酮与烯丙基醇在樟脑磺酸和硫酸镁存在下于 130 ℃ 处理,通过缩合和克莱森重排,得到 2-烯丙基-2,3-二氢-1H-吲哚-3-酮,收率很高。通过 NOE 实验确定了产物的立体化学性质。
Synthesis of 1,2-Dihydro-2-allylindol-3-ones Using in Situ Claisen Rearrengement of 1,2-Dihydroindol-3-ones with Allyl Alcohols.
Thermal treatment of 1, 2-dihydroindol-3-ones (2) with allyl alcohols (3) in the presence of camphorsulfonic acid and magnesium sulfate advances a sequence of condensation and Claisen rearrangement to give 1, 2-dihydro-2-allylindol-3-ones (6) including 2-(1, 1-dimethylallyl) derivatives (1).
Treatment of 2-allyl-1,2-dihydroindol-3-ones 1 with phosphonium ylides 2 in refluxing toluene gives 3-indole acetates 4 in good yields by tandem Wittig reaction and aromatization induced Cope rearrangement.
2-Alkyl-1,2-dihydroindol-3-ones are prepared from readily available 1-acetyl-2-methoxy-1,2-dihydroindol-3-one by alkylation, reduction with sodium borohydride, and demethoxylation of the resulting 3-hydroxy-2-methoxy-2,3-dihydroindoles with Lewis acids. The stereochemistry of the reduction is also described.