Catalytic asymmetric synthesis of 3-hydroxyl-2-oxindoles via enantioselective Morita–Baylis–Hillman reaction of isatins
作者:Ci-Ci Wang、Xin-Yan Wu
DOI:10.1016/j.tet.2011.02.045
日期:2011.4
The enantioselectiveMorita–Baylis–Hillmanreaction of acrylates to isatins was investigated for the first time, employing bifunctional phosphinothiourea organocatalysts based on chiral cyclohexane scaffold. The 3-hydroxyl-2-oxindole derivatives were obtained in excellent yields with moderate enantioselectivity (up to 69% ee) in the presence of 10 mol % catalyst 1b.
Enantioselective Morita−Baylis−Hillman Reaction of Isatins with Acrylates: Facile Creation of 3-Hydroxy-2-oxindoles
作者:Fangrui Zhong、Guo-Ying Chen、Yixin Lu
DOI:10.1021/ol102597s
日期:2011.1.7
amine catalyzed enantioselective Morita−Baylis−Hillman (MBH) reaction of isatins with acrylates has been demonstrated, allowing asymmetric synthesis of biologically significant 3-substituted-3-hydroxy-2-oxindoles in good yields and with excellent enantioselectivities. The C6′−OH group of β-isocupreidine (β-ICD) is believed to facilitate the key proton transfer step in the MBH reaction, via an intramolecular
was applied successfully in the synthesis of chiral cyclic spiropyrrolizidineoxindole and γ‐butyrolactone derivatives without enantioselectivity deterioration. The possible mechanism of this MBH reaction was also investigated by 31P NMR, ESI‐MS and KIE studies. The KIE experiments show that the electrophilic addition of N‐methyl isatin to the complex of acrylate ester and phophine‐squaramide is the rate‐determing
从廉价且可商购的β-氨基醇中以中等收率合成了一系列高度可调的双功能膦-方酸-甲酰胺H键供体有机催化剂6。催化剂6 F可有效地促进的不对称森田-的Baylis-希尔曼(MBH)反应ñ -烷基靛红与丙烯酸酯在提供良好的产率和对映选择性(高达93%的产率和手性3-取代的3-羟基-2-羟吲哚95%ee),其中具有挑战性的丙烯酸叔丁酯9 d提供了最佳ee迄今为止的价值。此外,该方法已成功地用于手性环状螺吡咯并咪唑恶唑和γ-丁内酯衍生物的合成,而对映选择性不降低。MBH反应的可能机理还通过31 P NMR,ESI-MS和KIE研究进行了研究。KIE实验表明,在丙烯酸酯和膦-方酸酰胺的配合物中亲电添加N-甲基伊斯廷丁是不对称MBH反应的决定速率的步骤。