Remote Substituents Controlling Catalytic Polymerization by Very Active and Robust Neutral Nickel(II) Complexes

Abstract

Remote control: Substituents strongly affect the catalytic properties of complexes 1 in ethylene polymerization, despite their remoteness from the active center. An appropriate substitution pattern provides very active and robust catalysts.

Facile synthesis of mono-, bis- and tris-aryl-substituted aniline derivatives in aqueous DMF

“…Aryl boronic acids bearing either electron-rich or electron-deficient groups demonstrated high reactivity and afforded the corresponding products in high yields in the presence of 0.5 mol% Pd(OAc) 2 (Table 4, entries 3 and 5). Cross-couplings involving mono-, diand trifluorophenyl boronic acids were all completed in short reaction times (Table 4, entries [6][7][8]. To the best of our knowledge, the present method is the first example for the synthesis of 2,6-bisaryl-4-nitroanilines in the absence of a ligand.…”

“…As far as we know, 2,6-bisarylaniline derivatives are very important intermediates to prepare N,N-bidentate ligands. [5][6] The present protocol is the simplest and most efficient method to construct these intermediates compared with the previous reports. [5][6] To our delight, fluoro-substituted phenyl boronic acids all gave good to excellent yields (Table 5, entries 5-7).…”

“…[5][6] The present protocol is the simplest and most efficient method to construct these intermediates compared with the previous reports. [5][6] To our delight, fluoro-substituted phenyl boronic acids all gave good to excellent yields (Table 5, entries 5-7). To further extend the scope of this methodology, we tried to carry out the Suzuki coupling of 4-bromoaniline with a series of aryl boronic acids.…”

“…Over the past decade, complexes synthesized from aniline derivatives have been a focus in organometallic chemistry and catalysis, such as N-heterocyclic carbene ligands (NHC) and β-diketiminate (nacnac) ligands. [5][6][7][8][9][10] So far, several approaches to the construction of mono-, bis-and tris-aryl-substituted aniline derivatives have been developed, such as nitration followed by reduction, [11][12] or via the palladium-catalyzed Suzuki reaction promoted by an oxygen and/or moisture sensitive ligand. [13][14][15][16][17][18] In 1995, Miura et al reported Pd(PPh 3 ) 4 as catalyst for the Suzuki reaction to synthesize mono-, di-, and triphenylanilines.…”

“…15 In 2004, Zuideveld et al described a protocol to afford 2,6-bisarylanilines via the Pd(PPh 3 ) 4 -catalyzed Suzuki reaction in toluene/ethanol/H 2 O. 6 Meinhard et al in 2007 reported a method to prepare 2,6-bisarylanilines using Pd(PPh 3 ) 4 in benzene. 4 Pisano reported the preparation of 2,6-diphenylaniline product with Pd(PPh 3 ) 4 in refluxing DME under N 2 to obtain 81% yield in 2 h. 18 …”