The Friedel-Crafts acylation of 1-acetylindoline with (S)-2- or (R)-2-(methanesulfonyloxy)propionyl chloride, and aluminum chloride in dichloromethane at room temperature did not afford the expected (S)- or (R)-1-acetyl-5-[2-(methanesulfonyloxy)propionyl]indoline, but gave optically pure (R)- or (S)-1-acetyl-5-(2-chloropropionyl)indoline, whose stereochemistry at the asymmetric carbon was inverted during the reaction. Similar reaction of 1-acetylindoline with the same chiral acylating agents in the presence of aluminum bromide gave mainly the corresponding 2-bromopropionyl derivatives, but as stereo mixtures.
室温下,1-
乙酰基吲哚啉与(S)-2-或(R)-2-(
甲磺酰氧基)
丙酰氯和
氯化
铝在
二氯甲烷中进行弗里德尔-卡夫酰化反应,没有得到预期的(S)-或(R)-1-
乙酰基-5-[2-(
甲磺酰氧基)丙酰基]
吲哚啉、但却得到了光学纯度为(R)-或(S)-1-
乙酰基-5-[2-(
甲磺酰氧基)丙酰基]
吲哚啉,其不对称
碳的立体
化学结构在反应过程中发生了颠倒。1-
乙酰基吲哚啉与相同的手性酰化剂在
溴化
铝存在下发生类似反应,主要得到相应的 2-
溴丙酰基衍
生物,但为立体混合物。