Asymmetric Transfer Hydrogenation of C=O and C=N Bonds Catalyzed by [Ru(η6 arene)(diamine)] Complexes: A Multilateral Study

Abstract

In these days, asymmetric transfer hydrogenation (ATH) is a very attractive method for synthesis of enantioenriched chiral compounds, especially fine chemicals such as drugs or agrochemicals. In this review, several topics related to the asymmetric transfer hydrogenation of ketones and cyclic or acyclic imines are discussed. Initially, the reaction mechanism of the ATH of ketones and imines, mainly 3,4-dihydroisoquinoline derivates, is examined. Next, typical reaction conditions, structural effects of the catalyst and a substrate, and analytical methods used for ATH monitoring and practical applications of the ATH in the chemical industry are described.

Ruthenium(II) Tris‐Pyrazolylmethane Complexes in Transfer Hydrogenation Reactions

“…[21] A considerable number of ruthenium(II) arene complexes, bearing a wide diversity of co-ligands, has been intensively investigated, showing a variable catalytic activity. [22][23][24][25][26][27][28][29][30] The Touge group developed bifunctional Ru complexes, bearing an ether linkage between 1,2-diphenylethylenediamine (DPEN) and the η 6 -arene ligand, that catalyse TH with excellent enantioselectivity under mild reaction conditions. [31] In 2020, the reduction of ketones mediated by ruthenium(II) p-cymene complexes, containing quinoxalin-11-one derivatives or tryptanthrin-6-oxime, was reported by Potapov and Benassi, resulting in moderate to excellent yields with 2-propanol as the hydrogen donor.…”

“…Among them, ruthenium compounds have played a leading role, [15–20] and related work in this area by Noyori was awarded with the Nobel Prize in 2001 [21] . A considerable number of ruthenium(II) arene complexes, bearing a wide diversity of co‐ligands, has been intensively investigated, showing a variable catalytic activity [22–30] . The Touge group developed bifunctional Ru complexes, bearing an ether linkage between 1,2‐diphenylethylenediamine (DPEN) and the η 6 ‐arene ligand, that catalyse TH with excellent enantioselectivity under mild reaction conditions [31] .…”