手性二氢苯并[ e ]吲哚骨架的第一个催化不对称结构已经建立在高度非对映和对映选择性的模式下(30个实例,产率高达99%,> 95:5 dr,> 99%ee),它利用了手性磷酸与3-乙烯基吲哚的偶氮萘衍生物的[3 + 2]环环化反应。该反应也代表了氮杂萘衍生物与烯烃的首次催化不对称环环化,这不仅为构建对映体富集的二氢苯并[ e ]吲哚骨架提供了有用的方法,而且还促进了氮杂萘衍生物催化不对称反应的化学反应。
Silica-supported policresulen as a solid acid catalyst for organic reactions
摘要:
A new type of solid catalyst was prepared by coating a thin layer of policresulen, an inexpensive polymer prepared via condensation of 2-hydroxy-4-methylbenzenesulfonic acid and formaldehyde that has been used as commercially available drug, onto the surface of silica. The policresulen component is insoluble in many organic solvents and can be adsorbed on silica with the aid of hydrogen bonding. The obtained silica/policresulen composite showed remarkable catalytic activity for various organic reactions. In model reactions, the catalyst can be recycled several times without significant loss of activity. The salient features of using this acid catalyst in organic reactions include cost-effectiveness, simple and time-efficient preparation, and the convenience of controlling the acid loading on the solid. (C) 2015, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.