Copper‐Catalyzed Intermolecular Hydroamination of Arylamines or Aza‐Heterocycles with Nitrostyrene Derivatives

Abstract

A new copper-catalyzed protocol for the intermolecular anti-Markovnikov addition of arylamines or heterocycles to terminal and unsymmetrical 1,2-disubstituted vinylarenes has been developed. The direct hydroamination is catalyzed by a readily available N-heterocyclic carbene-based copper complex and KOt-Bu, and the use of MeOH as an additive enhances the reactivity. The method provides a broad range of new and versatile amine compounds bearing various functional groups in good to excellent yields. a] Reaction conditions: nitrostyrene 1 a (0.40 mmol), amine 2 (0.48 mmol), MeOH (0.40 mmol), IPrCuCl (5 mol%), KOt-Bu (5 mol%), toluene (1.0 M) under N 2 . [b] Yields of the isolated products. The reaction time was 7 h for 3 aa-3 ag and 12 h for 3 ah-3 aq.

Copper‐Catalyzed Regio‐ and Stereoselective 1,6‐Conjugate Addition of Aza‐Heterocycles to 1‐Sulfonyl‐1,3‐dienes

“…First, we attempted to examine copper catalysts based on 1,2-bis(diphenylphosphino)benzene (dppbz) and bis [(2-diphenylphosphino)phenyl] ether (DPEphos), which were highly effective in our previous studies involving Cu-catalyzed aza-1,4-conjugate additions of (hetero)arylamines to α,β-unsaturated carbonyls and α, β-unsaturated sulfones. [10] The strong electron-donating properties of NHC ligands were expected to be able to activate pyrazole for addition to diene 1 by enhancing its nucleophilicity. Therefore, we investigated the ability of NHC-based copper catalysts to promote the selective 1,6-conjugate addition reaction.…”

“…Therefore, we investigated the ability of NHC-based copper catalysts to promote the selective 1,6-conjugate addition reaction. [10] The strong electron-donating properties of NHC ligands were expected to be able to activate pyrazole for addition to diene 1 by enhancing its nucleophilicity. [11] To our delight, when the reaction was carried out in the presence of IPrCuCl and KOt-Bu at 70°C for 15 h, pyrazole was added at the δ-position of diene 1, affording desired (E)-selective allylic amine product 3 a in 50% yield with 86:14 regioselectivity (3 a:4 b), albeit with the generation of 5% of (Z)-isomer 4 a, 3% of vinyl sulfone 4 c and 17% of diaminated product 4 d as the main side product (entries 1 and 2).…”

“…However, these bidentate phosphine ligands in the presence of CuCl and KO t ‐Bu did not promote the aza‐1,6‐addition of 2 a to diene 1 to provide desired allylic amine product 3 a (<5% conv, <2% of 3 a ). Therefore, we investigated the ability of NHC‐based copper catalysts to promote the selective 1,6‐conjugate addition reaction . The strong electron‐donating properties of NHC ligands were expected to be able to activate pyrazole for addition to diene 1 by enhancing its nucleophilicity .…”

Catalyst H-ZSM 5 in Amines addition on Carbonyl Compounds α, β-unsaturated catalyzed by H-ZSM 5

“…Following the addition Michael [13], there is a practical method has been developed for the addition of aliphatic or aromatic amines to alkenes [14], catalyzed by a heterogeneous catalyst [15], in this sense we can be carried out our addition amines on α, β-unsaturated alkenes [16].…”

A Commercially Available and User‐Friendly Catalyst for Hydroamination Reactions under Technical Conditions

“…Seminal work by Müller and co‐workers hinted the potential of even very simple salts of late transition metals as hydroamination catalysts, including [Cu(NCMe) 4 ](PF 6 ) , . Great advances have been achieved since in the intra‐ or intermolecular hydroaminations of alkynes and alkenes, although the catalytic systems reported are typically air‐sensitive/not readily available or use extremely toxic CuCN , . Hence, in a quest for a readily available copper(I) catalyst for hydroamination reactions, we decided to go back to tetrakis‐acetonitrile copper(I) derivatives and develop reactions as user‐friendly as possible by avoiding high purity solvents, and oxygen‐ or moisture‐free conditions.…”