Diastereo- and enantioselective reductive amination of cycloaliphatic ketones by preformed chiral palladium complexes

Abstract

Chiral cycloaliphatic amines were obtained from the direct asymmetric reductive amination of cycloaliphatic ketones using a preformed chiral palladium catalyst.

Unsupported Nanoporous Gold Catalyst for Chemoselective Hydrogenation Reactions under Low Pressure: Effect of Residual Silver on the Reaction

“…Reductive amination is considered as one of the important and atom economical methods to prepare amines . Traditional methods which use an equal amount of inorganic hydrides are not atom economical, but the use of transition metals along with hydrogen gas is considered as an atom-economical approach . Nevertheless, this type of reaction is similar to the reaction via a two-step, one-pot procedure; hence, formation of series of byproducts is an unavoidable issue.…”

The first example of asymmetric hydrogenation of imines with Co2(CO)8/(R)-BINAP as catalytic precursor

“…(1)) with Co 2 (CO) 8 /rac-BINAP ( Table 1). The reduction of 3a was not observed when working only with hydrogen (H 2 ) (entry 1), however, in the presence of CO/H 2 mixtures (3:1) (entries 2-4 and 7) good yields were obtained, behavior that suggests the stabilization of the catalytic species by CO partial pressure [40].…”

“…Likewise, several methodologies have been developed for the enantioselective reduction of imines [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], the asymmetric hydrogenation of functionalized imines such as acyclic aromatic N-aryl imines [29], ␣-fluorinated iminoesters [30,31] and acyclic imines [32], with a variety of complexes of Ir [32,33], Ru [34], Rh [19] and organocatalysts [35,36] have been employed in asymmetric hydrogenations and/or transfer hydrogenations of imines. Noteworthy, Co 2 (CO) 8 /modified phosphine complexes have never been used as catalysts in asymmetric hydrogenation of imines, even though, phosphine dicobalt octacarbonyl derivatives play an important role as catalytic promotors in other organic transformations, for example: hydroformylation of alkenes (also known as oxo process discovered in 1938 by Otto Roelen) [37,38], amidocarbonylation reaction [39,40], synthesis of quinolines [41], synthesis of ␤-lactams [42] and the Pauson-Khand reaction (PKR) [43][44][45].…”

One‐Pot Reductive Amination of Aromatic Aldehydes in [Et3NH][HSO4] using Sodium Borohydride and A Mechanistic Investigation using Computational Method

“…Reductive amination [19–26] of carbonyl compounds has been identified as the most effective and versatile method to synthesize secondary amines, surpassing several other methods such as Gabriel synthesis, [27–28] reduction of nitrogen‐containing compounds, [29–32] and alkylation of ammonia and amines [33–34] . Several catalyst systems and reducing reagents have been explored in reductive amination, following direct [35–42] as well as indirect procedures [43–44] . However, most of them suffered from one or more drawbacks, such as harsh reaction conditions, use of expensive and flammable reagents, complex and toxic metal catalyst systems, poor yields in spite of high conversion of aldehydes in some cases, low chemical selectivity, generation of toxic byproducts, and so on [45–51] .…”