Asymmetric (Transfer) Hydrogenation of Imines

Enantioselective Transformations in the Synthesis of Therapeutic Agents

“…To address these challenges, highly efficient and practical catalytic systems have been developed for the asymmetric hydrogenation of imine derivatives during the past decades, leading to high reactivities and enantioselectivities. 97 Among different imine substrates, cyclic imines exist as a single geometric isomer and therefore their reduction is less of a challenge. Accordingly, the enantioselective hydrogenation of cyclic imines has been employed as a key step in manufacturing drug molecules containing chiral cyclic amine motifs.…”

“…Finally, due to the basic and nucleophilic nature of chiral amine products that can coordinate to the metal, catalyst poisoning tends to occur and inhibits the catalytic activity. To address these challenges, highly efficient and practical catalytic systems have been developed for the asymmetric hydrogenation of imine derivatives during the past decades, leading to high reactivities and enantioselectivities …”

Primary trifluoroborate-iminiums enable facile access to chiral α-aminoboronic acids via Ru-catalyzed asymmetric hydrogenation and simple hydrolysis of the trifluoroborate moiety

“…Moreover, the use of pTIMs would eliminate the N -deprotection step to obtain the free amino group, thereby shortening the overall synthetic sequence. However, the unprotected N–H imine functionality is considered challenging and thus underexplored in the area of asymmetric hydrogenation (Scheme 1), 36–38 which suggests that asymmetric hydrogenation of pTIMs might be a demanding task. Herein, we present the results of our investigation that started with the preparation of a structurally diverse array of a novel subtype of TIM, i.e.…”

Developing Ru-Catalysts for Asymmetric Transfer Hydrogenation of Acyclic Imines

“…Enantiomerically pure chiral amines are a structurally important motif for the manufacture of products in both pharmaceutical and agrochemical industries . Transition-metal-catalyzed asymmetric hydrogenation (AH) and asymmetric transfer hydrogenation (ATH) of the corresponding imines are two of the most efficient and straightforward strategies for preparing optically active chiral amines. − Instead of employing H 2 gas, the use of nongaseous hydrogen donors including alcohols, formic acid, etc. makes ATH an operationally simple and safe protocol that has also been widely used in academia and industry …”