Borrowing Hydrogen Amination Reactions: A Complex Analysis of Trends and Correlations of the Various Reaction Parameters

Abstract

Borrowing hydrogen or the hydrogen autotransfer amination is a powerful approach to create single C–N bonds, starting from stable and readily available substrates: amines and alcohols. It is considered as one of the most atom-efficient and green methods to synthesize complex amines. Herein, we attempted to arrange the array of the existing data in a comprehensive and structured manner and determine correlations between the experimental conditions and catalysis outcome both within different groups of catalysts and between the defined groups using the machine analysis. For each type of N-nucleophiles (aromatic, aliphatic, and heteroaromatic amines, amides), the most efficient working conditions were suggested, including attributing the optimal base and temperature regime for each metal.

General Construction of Amine via Reduction of N=X (X = C, O, H) Bonds Mediated by Supported Nickel Boride Nanoclusters

“…Among these methods, the reduction of N= X ( X = C, O, H) bonds plays a key role. Generally, nitriles, nitro compounds and amides can be reduced to primary amines using borane [ 21 , 23 , 24 ], silane [ 25 ], hydrides [ 26 ], formats [ 20 , 27 ], alcohols [ 28 ], or molecular hydrogen [ 29 ]. Since Raney Ni was first prepared in 1905, it has become one of the most important catalysts for reduction.…”

“…To improve this, researchers have developed a variety of homogeneous or heterogeneous catalysts. For example, non-precious metals, such as iron [ 31 , 32 , 33 , 34 , 35 , 36 ], cobalt [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ], copper [ 48 , 49 ], nickel [ 10 , 11 , 21 , 24 , 50 , 51 , 52 , 53 ], manganese [ 6 , 54 , 55 ], and noble metals, such as palladium [ 19 , 56 , 57 , 58 ], platinum [ 59 ], ruthenium [ 8 , 60 , 61 , 62 ], rhodium [ 28 , 63 , 64 , 65 ], samarium [ 66 ], and iridium [ 67 ], have been employed to construct hydrogenation catalysts.…”

Disarming the alkoxide trap to access a practical FeCl3 system for borrowing-hydrogen N-alkylation

“…2 As a sustainable methodology using alcohol to synthesize nitrogen-containing compounds, borrowing-hydrogen reactions have attracted much interest recently. 2–7…”

“…2 As a sustainable methodology using alcohol to synthesize nitrogen-containing compounds, borrowing-hydrogen reactions have attracted much interest recently. 2- 7 Watanabe 8 and Grigg 9 described the early reports of N-alkylation of amines with alcohols in the presence of homogeneous catalysts in the 1980s. Since then, various catalytic systems based on precious metals have been reported, such as Ru-, [10][11][12][13][14] Rh-, 15,16 and Ir-based [17][18][19][20][21][22][23] systems.…”

Direct synthesis of functionalized 3-pyrrolidines and 4-piperidines using the borrowing hydrogen methodology

“…[1][2][3][4][5] Among them, piperidines and pyrrolidines are respectively the 6-membered and 5-membered most prevalent nitrogen rings system in U.S. FDA approved drugs. 6 Their preparation from acyclic precursors often involve multi step synthesis, 7 but over the recent years, borrowing hydrogen methodology [8][9][10][11][12][13] has emerged as a powerful tool for the synthesis of saturated aza-heterocycles from primary amines and diols. The general mechanism of this atom-efficient method is an in situ process organized through three different steps: (i) catalytic dehydrogenation of an unreactive alcohol to form the corresponding carbonyl compound (ii) condensation of the soformed carbonyl compound with an amine to generate in situ the corresponding imine (iii) hydrogenation of the imine using the hydrogen stored by the metal catalyst (Scheme 1).…”