Ruthenium‐Catalyzed Direct Asymmetric Reductive Amination of Diaryl and Sterically Hindered Ketones with Ammonium Salts and H₂

Abstract

A Ru‐catalyzed direct asymmetric reductive amination of ortho‐OH‐substituted diaryl and sterically hindered ketones with ammonium salts is reported. This method represents a straightforward route toward the synthesis of synthetically useful chiral primary diarylmethylamines and sterically hindered benzylamines (up to 97 % yield, 93–>99 % ee). Elaborations of the chiral amine products into bioactive compounds and a chiral ligand were demonstrated through manipulation of the removable and convertible ‐OH group.

Cobalt‐Catalyzed Chemo‐ and Enantioselective Hydrogenation of Conjugated Enynes

“…[2] However, to date, most studies have been limited to the enantioselective reduction of substrates bearing a single unsaturated bond. [3] Less attention has been directed towards the simultaneous chemo-and enantioselective hydrogenation of the relatively inert unsaturated group in substrates possessing multiple unsaturated bonds, despite there being a huge demand in practical applications. [4] It is understood that the reactivity of the C C bond is usually much higher than other unsaturated C = C, C=N, and C=O bonds in the catalytic reduction reaction.…”

Practical N-alkylation via homogeneous iridium-catalyzed direct reductive amination

“…For the substituted arylethanones, in general the electronic property of the substituents on the aromatic ring of the ketone substrates appeared to have limited effects on the reaction yields. To our delight, various functional groups, such as chloride, ethers, thio-ether and sulphone, were all well-tolerated without being reduced (products [36][37][38][39][40]44). For other aryl and aliphatic ketones, their DRA reactions with benzyl amine proceeded smoothly to afford the corresponding products.…”

“…As a result, frequently those catalytic procedures suffer narrow substrate scope, requirement of excess additives, high catalyst loading, high reaction temperature and/or synthetically demanding catalytic complexes and ligands. [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] To date, successful universal catalytic systems with broad substrate scope are extremely scarce. [41][42][43][44][45][46] In this regard, highly efficient and practical homogeneous catalytic systems for more functional group tolerating with low catalyst loading and simplified and inexpensive ligands are immensely desired.…”