Aerobic catalytic systems inspired by copper amine oxidases
Abstract The goal of sustainable development has been accepted as a common policy in current society. In response to this challenge, the development of green processes which utilize environmentally benign oxidants, reduce chemical waste and handling costs, is highly desirable. Given the widespread importance of imines as pivotal synthetic intermediates and essential pharmacophores in numerous biologically active compounds, various catalytic methods allowing the aerobic oxidation of amines to imines have been developed. Recently, noticeable progress has arisen from the discovery of various quinone-based catalytic systems, inspired by copper amine oxidase enzymes (CuAOs), which are able to reproduce the selectivity of CuAOs for primary amines and even to expand the amine substrates scope. However, the need for synthesizing these catalysts prior use adversely affects the economics as well as the eco-friendly nature of the method. To surpass these drawbacks, the “second-order” biomimicry idea has been recently advanced to describe a system in which in situ modification of pre-catalyst components affords the active biomimetic catalyst. This minireview especially covers our recent contribution to the design of bioinspired quinone-based catalysts for the aerobic oxidation of amines to imines which has culminated in a dual bioinspired protocol as an example of “second-order” biomimicry.