Making Dimethylamino a Transformable Directing Group by Nickel‐Catalyzed CN Borylation

Abstract

The dimethylamino (Me2N) group is arguably the most versatile functional group capable of highly efficient and site-selective directed aromatic functionalizations at the ortho-, meta-, and para-positions depending on reaction conditions. While the repertoire of Me2N-directed reactions is growing at a rapid pace, the lack of a general method to transform this group to other functionalities hampers its wider application in organic synthesis. Here we report nickel-catalyzed C-N borylations of aryl- and benzyl-dimethylamines that permit the conversion of a huge library of largely underutilized Me2N-containing organic molecules into various functional molecules by taking advantage of the wealth of existing C-B functionalization methods.

Phenyltrimethylammonium Salts as Methylation Reagents in the Nickel‐Catalyzed Methylation of C−H Bonds

“…[2][3][4][5][6] Our experimental results indicate that phenylation did not take place under the reaction conditions when using the Ni II complex as the catalyst precursor,a nd the reported fact that phenyltrimethylammonium salts function as phenylation reagents in various cross-coupling reactions when using Ni 0 complexes suggest that Ni 0 is not ak ey catalytic species in the present methylation reaction. [2][3][4][5][6] Our experimental results indicate that phenylation did not take place under the reaction conditions when using the Ni II complex as the catalyst precursor,a nd the reported fact that phenyltrimethylammonium salts function as phenylation reagents in various cross-coupling reactions when using Ni 0 complexes suggest that Ni 0 is not ak ey catalytic species in the present methylation reaction.…”

“…Wenkert and co-workers have reported Ni-catalyzed Kumada-Tamao coupling with aryltrimethylammoinium iodide. [6,8] However,the use of ammonium salts as methylation reagents in cross-coupling reactions has never been reported (Scheme 1). Quite recently,a ryltrimethylammonium triflates have been used as CÀHarylation reagents in the Pdcatalyzed arylation of azoles.…”

“…Wenkert and co-workers have reported Ni-catalyzed Kumada-Tamao coupling with aryltrimethylammoinium iodide. [2] Later, Nicatalyzed Suzuki-Miyaura coupling, [3] Negishi coupling, [4] amination, [5] and borylation [6] with aryltrimethylammonium salts were reported. Quite recently,a ryltrimethylammonium triflates have been used as CÀHarylation reagents in the Pdcatalyzed arylation of azoles.…”

“…[7] Benzyltrimethylammonium salts have also been used as benzylating reagents in crosscoupling reactions. [6,8] However,the use of ammonium salts as methylation reagents in cross-coupling reactions has never been reported (Scheme 1). [9] We report herein the Nicatalyzed methylation of CÀHb onds in aromatic amides with phenyltrimethylammonium salts,w hich function as methylation reagents.…”

Nickel-catalysed retro-hydroamidocarbonylation of aliphatic amides to olefins

“…Herein we disclose the first case of a retro-hydroamidocarbonylation process by chemoselective activation of aliphatic amide C–N bonds using nickel-catalysis23242526272829.…”