Simultaneous Functionalization and Cyclization of 2-Ethynylaniline Derivatives to Indoles
摘要:
Two different kind of sequential cyclization-functionalization are developed. Namely, cyclization-chlorination of 2-ethynylaniline derivatives using CuCl2 gave 3-chloro- and 3,5-dichloroindole derivatives. The plausible mechanism for this reaction is also discussed. On the other hand, the reaction between 2-ethynylaniline derivatives and Cu(NO3)(2)center dot 3H(2)O in THF provided C4-nitro compound. After being changed the solvent from THF to DMF, followed by heating, 5-nitroindole derivatives was afforded.
Efficient construction of indole rings from 2-ethynylaniline derivatives catalyzed by copper(II) salts and its application to the tandem cyclization reactions
The efficient cyclization reactions of the N-methanesulfonyl or N-ethoxycarbonyl derivatives of 2-ethynylanilines, functionalized on the benzene ring and/or the acetylene terminal into indoles catalyzed by either Cu(OTf)2 or Cu(OAc)2 are accomplished. The application of this reaction to the tandem cyclization reaction is also described.
Mild and efficient cyclization reaction of 2-ethynylaniline derivatives to indoles in aqueous medium
作者:Kou Hiroya、Shin Itoh、Takao Sakamoto
DOI:10.1016/j.tet.2005.08.098
日期:2005.11
Results of the optimized cyclization reaction of 2-ethynyl aniline derivatives to indoles catalyzed by copper(II) salts are described. The reactions can be carried out in a mixture of H2O and MeOH in the presence of 1-ethylpiperidine at room temperature. These conditions can be applied to a bulky substrate, which is difficult to be cyclized efficiently by existing reaction conditions. Furthermore, this reaction condition was applied to a catalyst recycling reaction system. (c) 2005 Elsevier Ltd. All rights reserved.