An Imidazoline-Aminophenol (IAP) Nickel Catalyst: Structure and Catalytic Activity in the Enantioselective 1,4-Addition of 3′-Indolyl-3-Oxindoles to Nitroethylene
作者:Atsuko Awata、Makiko Wasai、Hyuma Masu、Sayaka Kado、Takayoshi Arai
DOI:10.1002/chem.201304456
日期:2014.2.24
The structure of a nickel complex of imidazoline–aminophenol (IAP) prepared from IAP with Ni(OAc)2 was elucidated as cis‐bis(imidazolineaminophenoxide) [Ni(IAP)2]. The [Ni(IAP)2] complex smoothly promoted catalytic asymmetric 1,4‐addition of 3′‐indolyl‐3‐oxindole to nitroethylene to provide chiral mixed 3,3′‐bisindoles with high enantioselectivities. Mechanistic studies using ESI‐MS analyses suggest
由IAP与Ni(OAc)2制备的咪唑啉-氨基苯酚(IAP)镍配合物的结构被阐明为顺式-双(咪唑啉氨基苯氧化物)[Ni(IAP)2 ]。[Ni(IAP)2 ]配合物平稳地促进了3'-吲哚基-3-氧吲哚向硝基乙烯的催化不对称1,4-加成反应,从而提供了具有高对映选择性的手性混合3,3'-双吲哚。使用ESI-MS分析的机理研究表明,一种IAP配体从[Ni(IAP)2 ]上解离生成3'-吲哚基-3-氧吲哚的Ni-烯酸酯。从光学活性的3,3'-混合吲哚加合物,以三步反应顺序成功地合成了生物学上重要的3'-吲哚基-3-吡咯烷二氢吲哚。