Nickel‐Catalyzed N‐Alkylation of Acylhydrazines and Arylamines Using Alcohols and Enantioselective Examples

Abstract

Aborrowing-hydrogen reaction between amines and alcohols is an atom-economic wayt op repare alkylamines, ideally with water as the sole byproduct. Herein, nickel catalysts are used for direct N-alkylation of hydrazides and arylamines using racemic alcohols.Moreover,anickel catalyst of (S)-binapine was used for an asymmetric N-alkylation of benzohydrazide with racemic benzylic alcohols.

New Access Routes to Privileged and Chiral Ligands for Transition‐Metal Catalyzed Hydrogen Autotransfer (Borrowing Hydrogen), Dehydrogenative Condensation, and Alkene Isomerization Reactions

“…(�)-syn-2,3-Diphenylbutane-1,4-diol (69). Obtained by borane reduction [118] of trans-2,3-diphenylsuccinic acid, which itself was obtained through oxidative coupling of ethyl phenylacetate.…”

“…Relying on structurally related Iridium complexes, Wang and coworkers reported the atropoenantioselective preparation of axially chiral biaryl compounds in an asymmetric amination reaction, starting from racemic 2’‐(hydroxymethyl)‐[1,1’‐biphenyl]‐2‐ols [67] . Asymmetric N ‐alkylation were also reported by Beller and coworkers who developed enantioselective access to oxazolidine derivatives employing chiral ruthenium catalysts, [68] and by Zhou and coworkers who used chiral nickel‐based systems to achieve enantioselective N‐alkylation of acyl hydrazines [69] . Consequently, a major goal of the current study was to develop synthetic methods to provide ready access to ligands and pincer catalysts for catalytic BH/DHC and alkene isomerization chemistry in an efficient manner for exploration in various research projects.…”

“…[67] Asymmetric N-alkylation were also reported by Beller and coworkers who developed enantioselective access to oxazolidine derivatives employing chiral ruthenium catalysts, [68] and by Zhou and coworkers who used chiral nickel-based systems to achieve enantioselective N-alkylation of acyl hydrazines. [69] Consequently, a major goal of the current study was to develop synthetic methods to provide ready access to ligands and pincer catalysts for catalytic BH/DHC and alkene isomerization chemistry in an efficient manner for exploration in various research projects. With a view to exploring asymmetric transformations, we also targeted chiral, enantiopure versions of selected established catalysts that had been developed in the groups of Milstein, [46] Huang, [60,61] Kempe [51] and Grotjahn.…”

Highly Efficient and Selective N-Alkylation of Amines with Alcohols Catalyzed by in Situ Rehydrated Titanium Hydroxide

“…In the last few decades, three main strategies have been applied for amination of alcohols: (i) "Borrowing Hydrogen" methodology using either noble metal based Ru- [12], Pd- [13], Ir- [14], Rh- [15], and Pt- [16] complexes, and more recently non-noble metal Mn- [17,18], Co- [19,20,21], Ni- [22,23,24,25] and Fe- [26] complexes. Also various of heterogeneous catalysts [27,28,29,30,31,32,33,34] have been used.…”

Redox-enabled direct stereoconvergent heteroarylation of simple alcohols

“…Enantioselective variants of these transformations, on the other hand, have remained underdeveloped 22,23 . Highly enantioselective alkylation of amines and ketones has only been achieved in recent years by our group [24][25][26][27][28] , the Beller group 29 , the Donohoe group 30,31 , and others [32][33][34][35][36][37] to access chiral amines, ketones, alcohols, etc. The application of borrowing hydrogen strategy to an enantioconvergent heteroarylation, to our knowledge, has never been reported in the literature 38 .…”