Hydro-amination/-amidation of 1,3-diynes with indoles/azoles/amides under modified Ullmann conditions: stereo- and regio-selective synthesis of N-alkenynes via N–H bond activation

Characterization and photocatalytic behavior of 2,9-di(aryl)-1,10-phenanthroline copper(i) complexes

“…2b Further interest in the complexes has arisen due to their unique structural, magnetic, electronic, and C-H functionalization 21 and hydroamidation. 22 Within this burgeoning new application of metal-phenanthroline complexes, a unique role for copper has emerged. Importantly, copper (I) is an inexpensive, earth-abundant, and attractive alternative to precious metal ions.…”

Cesium Carbonate‐Promoted Hydroamidation of Alkynes: Enamides, Indoles and the Effect of Iron(III) Chloride

“…Considering that most of the ortho ‐alkynylanilides 4 had been prepared by a route involving Sonogashira coupling of ortho ‐haloanilines,11 and taking into account the existing reports on palladium‐ or copper‐catalyzed hydroamidation and hydroamination reactions,6e–l,8a–h anilide 4c was prepared by a palladium‐free approach based on nucleophilic substitution on ortho ‐fluoronitrobenzene (Scheme ), and cyclization to 5c (Method A) provided the same yield (82%) from both the latter alkyne and that prepared by a Sonogashira‐based protocol. The content of the palladium and copper traces was measured (ICP‐MS) in the starting anilide 4c and in all the reagents involved (Cs 2 CO 3 ) and found to be below 6⋅10 −4 mol% and 9⋅10 −3 mol%, respectively.…”

“…With regard to the intermolecular version, the aforementioned metal traces were in all cases bellow 2⋅10 −4 mol%. Considering previous reports on copper‐catalyzed hydroamidation reactions,6j–l the presence of infinitesimal amounts of copper in the iron source of Method B (FeCl 3 ⋅6 H 2 O) was also carefully measured (1.4⋅10 −4 mol%) in order to discard this possibility. Therefore, although the co‐participation of copper traces17 in the reported hydroamidations cannot be ruled out, this possibility is unlikely due to the extremely low amounts of copper present in the reaction mixture.…”

Catalytic Hydrofunctionalization Reactions of 1,3-Diynes

“…As shown in Scheme 38, a catalytic system composed of TiCl 4 and tert-butylamine was also able to promote the coupling of an aliphatic 1,3-diyne with aromatic primary amines to afford pyrroles, albeit featuring a low efficiency [108]. On the other hand, intermolecular copper-catalyzed hydroamination reactions of aromatic 1,3-diynes with indole, imidazole, and pyrazole derivatives were described by Kundu and colleagues (Scheme 39) [109]. The reactions, conducted in DMSO at 100 • C with a CuI/Phen/Cs 2 CO 3 (Phen = 1,10-phenantroline) combination, afforded the linear N-alkenynes 68 in high yields as mixtures of the corresponding E and Z isomers, with the latter being predominant in all the cases.…”