82319-40-2Relevant academic research and scientific papers
A Bioinspired Organocatalytic Cascade for the Selective Oxidation of Amines under Air
Largeron, Martine,Fleury, Maurice-Bernard
, p. 6763 - 6767 (2017)
A bioinspired organocatalytic cascade reaction for the selective aerobic oxidative cross-coupling of primary amines to imines is described. This approach takes advantages of commercially available pyrogallol monomeric precursor to deliver low loadings of natural purpurogallin in situ, under air. This is further engaged in a catalytic process with the amine substrate affording, under single turnover, the active biomimetic quinonoid organocatalyst and the homocoupled imine intermediate, which is then converted into cross-coupled imine after dynamic transimination. This organocatalytic cascade inspired by both purpurogallin biosynthesis and copper amine oxidases allows the aerobic oxidation of non-activated primary amines that non-enzymatic organocatalysts were not able to accomplish alone.
A dual biomimetic process for the selective aerobic oxidative coupling of primary amines using pyrogallol as a precatalyst. Isolation of the [5 + 2] cycloaddition redox intermediates
Deschamps, Patrick,Fleury, Maurice-Bernard,Hammad, Karim,Largeron, Martine
, p. 1894 - 1905 (2020/04/07)
A bioinspired organocatalytic cascade reaction mimicking both purpurogallin biosynthesis and copper amine oxidases (CuAOs) activity is described, at room temperature under ambient air, for the activation of the α-C-H bond of primary amines. The reaction sequence uses low-cost commercially available pyrogallol as a precatalyst which undergoes an in situ oxidative self-processing step, resulting in its conversion into natural purpurogallin, a [5 + 2] cycloaddition redox intermediate. This is further involved in the CuAOs-like transamination mechanism for producing, under single turnover, the active biomimetic organocatalyst which mediates the selective oxidative coupling of primary amines, including the non-activated substrates of CuAOs. Without any metal cocatalyst or additives, the protocol gives access to cross-coupled imines as well as 1,2-disubstituted benzimidazoles. The isolation of not easily accessible [5 + 2] cycloaddition redox intermediates provides direct and clear evidence for the proposed dual biomimetic process.
A metalloenzyme-like catalytic system for the chemoselective oxidative cross-coupling of primary amines to imines under ambient conditions
Largeron, Martine,Fleury, Maurice-Bernard
, p. 3815 - 3820 (2015/03/04)
The direct oxidative cross-coupling of primary amines is a challenging transformation as homocoupling is usually preferred. We report herein the chemoselective preparation of cross-coupled imines through the synergistic combination of low loadings of CuII metal-catalyst and o-iminoquinone organocatalyst under ambient conditions. This homogeneous cooperative catalytic system has been inspired by the reaction of copper amine oxidases, a family of metalloenzymes with quinone organic cofactors that mediate the selective oxidation of primary amines to aldehydes. After optimization, the desired cross-coupled imines are obtained in high yields with broad substrate scope through a transamination process that leads to the homocoupled imine intermediate, followed by dynamic transimination. The ability to carry out the reactions at room temperature and with ambient air, rather than molecular oxygen as the oxidant, and equimolar amounts of each coupling partner is particularly attractive from an environmentally viewpoint.
A biologically inspired CuI/topaquinone-like co-catalytic system for the highly atom-economical aerobic oxidation of primary amines to imines
Largeron, Martine,Fleury, Maurice-Bernard
scheme or table, p. 5409 - 5412 (2012/06/18)
Acting together: Low catalytic amounts of CuI and topaquinone-like catalyst 1ox (see scheme) are sufficient to activate the α-C-H bond of primary amines, which are converted into alkylated imines under ambient conditions. This atom-economical process tolerates the presence of various reactive functional groups and allows selective cross-coupling of two amines. Copyright
