Reductive Coupling of Isatins with α,β-Unsaturated Carbonyl Compounds by Low-Valent Titanium
作者:Naoki Kise、Yuki Mitsui、Toshihiko Sakurai
DOI:10.1246/bcsj.20210357
日期:2022.1.15
The reductive coupling of isatins with α,β-unsaturated carbonyl compounds by Zn-TiCl4 in THF at 0 °C gave one-to-one coupled products, 3-hydoxy-3-alkyloxindoles. The coupled products obtained from α,β-unsaturated esters were transformed to the corresponding spiro-γ-lactones by refluxing in cat. PPTS/benzene. The two-to-one coupled products, 3,3-bis(2-carbomethoxyethyl)oxindoles, were formed by the
靛红与 α,β-不饱和羰基化合物在 0 °C 下通过 Zn-TiCl 4在 THF 中的还原偶联得到一对一的偶联产物,3-羟基-3-烷氧基吲哚。由α,β-不饱和酯获得的偶联产物通过在催化剂中回流转化为相应的螺-γ-内酯。PPTS/苯。2:1 偶联产物 3,3-双(2-碳甲氧基乙基)羟吲哚是通过 Zn-TiCl 4在 THF 中在 30 °C 下用丙烯酸甲酯还原靛红形成的。靛红与丙烯酸甲酯还原偶联得到的一对一偶联产物通过Zn-TiCl 4还原为3-(2-甲氧基乙基)羟吲哚在 30 °C 的 THF 中。将 3-(2- 碳甲氧基乙基) 羟吲哚加入丙烯腈中得到 3-(2- 碳甲氧基乙基)-3-(2-氰乙基) 羟吲哚。