Gannarapu Malla Reddy, Zhou Jun, Jiang Bingyao, Shibata Norio
Departments of Nanopharmaceutical Science & Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan.
Departments of Nanopharmaceutical Science & Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan; Institute of Advanced Fluorine-Containing Materials, Zhejiang Normal University, 688 Yingbin Avenue, 321004 Jinhua, China.
iScience. 2020 Apr 24;23(4):100994. doi: 10.1016/j.isci.2020.100994. Epub 2020 Mar 20.
We disclose the Cu-catalyzed enantioselective synthesis of 3-methyl-3-propargyl-indolines, which contain a quaternary stereogenic carbon center, via the decarboxylative [4 + 1] annulation of 4-methyl-4-propargyl-benzoxazinanones with variety of sulfur ylides. The reaction proceeds predominantly through a γ-attack at the Cu-allenylidene intermediates by sulfur ylides to provide the corresponding indolines in good yield and high enantioselectivity (up to 91% ee). In contrast, the reaction of 4-trifluoromethyl-4-propargyl-benzoxazinanones with sulfur ylides delivers 3-trifluoromethyl-2-functionalized indoles in good to high yield via an unexpected α-attack at the Cu-allenylidene intermediates. Control over the α/γ-attack at the Cu-allenylidene intermediates by the same interceptors was achieved for the first time by the use of trifluoromethyl substituents.
我们报道了通过4-甲基-4-炔丙基-苯并恶嗪酮与多种硫叶立德的脱羧[4 + 1]环化反应，实现了含有季碳手性中心的3-甲基-3-炔丙基-二氢吲哚的铜催化对映选择性合成。该反应主要通过硫叶立德对铜-亚丙二烯中间体的γ-进攻进行，以良好的产率和高对映选择性（高达91% ee）提供相应的二氢吲哚。相比之下，4-三氟甲基-4-炔丙基-苯并恶嗪酮与硫叶立德的反应通过对铜-亚丙二烯中间体的意外α-进攻，以良好至高的产率得到3-三氟甲基-2-官能化吲哚。通过使用三氟甲基取代基，首次实现了相同亲核试剂对铜-亚丙二烯中间体α/γ-进攻的控制。
