Largeron Martine, Fleury Maurice-Bernard
UMR 8638 CNRS-Université Paris Descartes (Paris 5), Sorbonne Paris Cité, Faculté de Pharmacie de Paris, 4 avenue de l'Observatoire, 75270 Paris cedex 06 (France).
Chemistry. 2015 Feb 23;21(9):3815-20. doi: 10.1002/chem.201405843. Epub 2015 Jan 21.
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 Cu(II) 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.
伯胺的直接氧化交叉偶联是一项具有挑战性的转化反应,因为通常更倾向于发生自身偶联。我们在此报告了在环境条件下,通过低负载量的铜(II)金属催化剂与邻亚氨基醌有机催化剂的协同组合,化学选择性地制备交叉偶联亚胺。这种均相协同催化体系的灵感来源于铜胺氧化酶的反应,铜胺氧化酶是一类具有醌有机辅因子的金属酶,可介导伯胺选择性氧化为醛。经过优化,通过转氨过程生成自身偶联亚胺中间体,随后进行动态转亚胺化反应,可在较宽的底物范围内以高产率获得所需的交叉偶联亚胺。从环境角度来看,能够在室温及环境空气中进行反应,而非以分子氧作为氧化剂,且各偶联反应物的用量为等摩尔量,这一点特别具有吸引力。