Innovative green oxidation of amines to imines under atmospheric oxygen

Abstract

In recent years, the development of environmentally benign molecular construction methods has been of great importance, and especially, resource recycling, high atomic efficiency, and low environmental impact are strongly demanded....

Tailoring flavin-based photosensitizers for efficient photooxidative coupling of benzylic amines

“…S4-48-67, ESI †). 99 These FLPSs are capable of sensitizing the photooxidative coupling of fluorobenzylamine derivatives and the product yields are more than 50% in most entries in batch runs. The product yields when DB-FL was used were always superior to those of the other FLPSs, independent of the substrate used (Table 7).…”

Green imine synthesis from amines using transition metal and micellar catalysis

“…16,18 In many cases, stoichiometric amounts of explosive or harmful reagents like peroxides or heavy metals are used, resulting in a corresponding amount of pollutants. [19][20][21][22] Catalysis is instrumental in the synthesis of imines to help enable reactions to take place under relatively mild reaction conditions and for shorter reaction times. Imine synthesis has been performed using both organocatalysts and transition metal catalysts.…”

“…25 Reviews for the catalytic formation of imines have previously described the synthesis of imines from inception to their current development by various techniques with different reactants and catalysts, such as using molecular oxygen instead of peroxides. 19,26 Such routes involved condensation reactions involving an amine and aldehyde, or aldehyde via alcohol starting material (Scheme 3). 27 This review aims to provide an overview and discussion of catalytic methods relevant to green chemistry for the preparation of imines, as introduced above.…”

A biomimetic approach to aerobic oxidation of amines in water via a redox-active cacotheline organocatalyst

“…3 The human body metabolizes proteins to amino acids using various enzymes, and the function of transaminases is responsible for the selective aminotransfer reaction between amino acids and 2-oxo acids for the clearance of amino acids. 4 While there are a number of transition metal-catalyzed oxidation protocols to convert amines to the corresponding (ket)imines, 5 the recent development of biomimetic aerobic oxidation approaches has offered the much-needed mechanistic insights into amine oxidases with a copper cofactor and monoamine oxidases with a flavin cofactor. 6 The designed transaminase catalysts have been shown to react with amines to give (ket)imine intermediates, which subsequently releases ortho -aminophenols for the crucial aerobic oxidation to ortho -iminoquinones as an active catalyst form (Scheme 1b).…”