Metal-Catalyzed Asymmetric Hydrogenation of C═N Bonds

Abstract

This review recaps the achievements in the field of metal-catalyzed asymmetric direct hydrogenation of nonactivated and activated imines. A summary of the reported catalytic systems with the corresponding reactivity, selectivity, and limitations are given including a discussion about the effects of some reaction conditions on the enantioselectivity of imine hydrogenation. An analysis of proposed imine hydrogenation mechanisms is discussed.

Rh-Catalyzed diastereoselective addition of arylboronic acids to α-keto N-tert-butanesulfinyl aldimines: synthesis of α-amino ketones

“…4 They are also versatile synthetic precursors in the efficient construction of chiral 1,2-amino alcohols 5 and vicinal diamine derivatives. 6 Consequently, continuous efforts have been devoted to the construction of chiral α-amino ketones, 7 including asymmetric cross-coupling of aldehydes with imines, 8 hydrogenation of ketimines 9 and insertion of α-diazo ketones or α-carbonyl sulfonium ylides, 10 and so on. 11 Although great advances have been made in this field, research on the synthesis of two aryl substituted chiral α-amino ketones is not sufficient due to their limited substrate scope (Scheme 1A).…”

Ce-Doped α-FeOOH as a High-Performance Catalyst for Atom-Economic Synthesis of Imines: Enhanced Oxygen-Activating Capacity and Acidic Property

“…Imines, as significant organic intermediates, have been widely used in the synthesis of pharmaceuticals, bioactive components, as well as fine chemicals. − The traditional preparation method involves the condensation of amines with unstable carbonyl compounds to imines with the aid of acid catalysts and dehydrating agents . A number of new synthetic routes have been developed in the past decade, − among which is the one-pot cross-coupling of alcohols with amines, a desirable research focus as the only byproduct is water and the substrates are inexpensive and readily available.…”

Asymmetric Synthesis of Protected Unnatural α-Amino Acids via Enantioconvergent Nickel-Catalyzed Cross-Coupling

“…The development of effective and straightforward methods to access enantioenriched unnatural (non-canonical) α-amino acids is a highly important objective, as these amino acids are finding widespread use in fields such as biology, biochemistry, pharmaceutical science, and materials science; − furthermore, they can readily be transformed into other useful families of chiral molecules, including β-amino alcohols (Figure ). , Catalytic asymmetric routes to unnatural α-amino acids are especially attractive, ,, and numerous approaches have been described, such as hydrogenations of olefins and imines, , electrophilic aminations of enolates, electrophilic alkylations of glycine derivatives, and nucleophilic additions to α-imino esters …”