作者:Naoki Kise、Kouta Sasaki、Toshihiko Sakurai
DOI:10.1016/j.tet.2014.10.071
日期:2014.12
The reductive coupling of isatins with ketones and aldehydes by Zn–TiCl4 in THF gave two- and four-electron reduced products, 3-hydoxy-3-(1-hydoxyalkyl)oxindoles and 3-alkylideneoxindoles, selectively by controlling the reaction conditions. Although the 3-(1-hydoxyalkyl)oxindoles were also produced as the four-electron reduced products in some cases, these products were readily dehydrated to 3-alkylideneoxindoles
Zn-TiCl 4在THF中将靛红与酮和醛还原偶联,可通过控制反应条件选择性地产生两电子还原产物和3-电子还原产物3-羟基-3-(1-羟基烷基)-吲哚和3-烷基亚乙基吲哚。尽管在某些情况下3-(1-羟烷基)恶吲哚也作为四电子还原产物产生,但这些产物容易脱水成3-亚烷基氧杂吲哚。衍生自醛的3-亚烷基氧杂吲哚形成为几何异构体的混合物。通过在催化剂中回流,将两种几何异构体异构化成平衡混合物。PPTS /苯。