Aerobic copper-catalyzed organic reactions.
Aerobic copper-catalyzed organic reactions.
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DOI：
10.1021/cr300527g
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发表时间：
2013-08-14
期刊：
影响因子：
62.1
通讯作者：
Kozlowski, Marisa C.
中科院分区：
文献类型：
--
作者：
Allen, Scott E.;Walvoord, Ryan R.;Padilla-Salinas, Rosaura;Kozlowski, Marisa C.
铜的化学性质非常丰富，因为它可以很容易地进入Cu 0，CuI，CuII和CuIII氧化态，使其能够通过单电子或双电子过程发挥作用。因此，自由基途径和强大的双电子键形成途径，通过有机金属中间体，类似于钯，可以发生。此外，铜的不同氧化态通过刘易斯酸相互作用或π-配位与大量不同的官能团良好缔合。总之，这些特征赋予了非常广泛的活性，允许铜催化许多底物的氧化和氧化结合。氧气是一种高度原子经济、环境友好和丰富的氧化剂，这使得它在许多方面都是理想的。1.氧反应的高活化能要求使用催化剂。2与分子氧结合，铜催化的化学性质呈指数级增加，因为氧可以作为电子的吸收器（氧化酶活性）或结合到产物中的氧原子的来源（加氧酶活性）或两者。铜与氧的氧化是一个容易的过程，允许在净氧化过程中的催化周转，并随时进入更高的CuIII氧化态，这使得一系列强大的转换，包括双电子还原消除到CuI。分子氧也不会受到有毒副产物的阻碍，这些有毒副产物或者偶尔经由H2 O2（氧化酶活性）被还原成水，或者以高原子经济性（加氧酶活性）被掺入靶结构中。这种使用氧气或空气（21%氧气）的氧化已经安全地用于许多商品化学品的连续和间歇工艺中。3然而，使用挥发性烃溶剂的间歇式反应器要求顶部空间中的氧浓度保持较低（通常< 5 - 11%），以避免可燃混合物，这可能限制反应混合物中的氧浓度。4− 6已经开发了许多替代方法，允许在更广泛的条件下安全使用氧化化学。例如，使用二氧化碳代替氮气作为稀释剂导致可燃性降低。或者，可以加入水以缓和可燃性，甚至允许使用纯氧。6新的反应器设计还允许通过在溶剂中保持气泡而使用纯氧代替稀释的氧气，这大大提高了反应速率并防止在顶部空间中积累更高浓度的氧气。4a，7已发现超临界二氧化碳作为溶剂是有利的，这是由于其对氧化剂的化学惰性和其在宽温度范围内与氧气或空气的完全可溶解性。8许多流动技术9包括流动反应器、10毛细管流动反应器、11微通道/微结构反应器、12和膜反应器13。
The chemistry of copper is extremely rich because it can easily access Cu0, CuI, CuII, and CuIII oxidation states allowing it to act through one-electron or two-electron processes. As a result, both radical pathways and powerful two-electron bond-forming pathways via organometallic intermediates, similar to those of palladium, can occur. In addition, the different oxidation states of copper associate well with a large number of different functional groups via Lewis acid interactions or π-coordination. In total, these features confer a remarkably broad range of activities allowing copper to catalyze the oxidation and oxidative union of many substrates. Oxygen is a highly atom-economical, environmentally benign, and abundant oxidant, which makes it ideal in many ways. 1 The high activation energies in the reactions of oxygen require that catalysts be employed. 2 In combination with molecular oxygen, the chemistry of copper catalysis increases exponentially since oxygen can act as either a sink for electrons (oxidase activity) or a source of oxygen atoms that are incorporated into the product (oxygenase activity) or both. The oxidation of copper with oxygen is a facile process allowing catalytic turnover in net oxidative processes and ready access to the higher CuIII oxidation state, which enables a range of powerful transformations including two-electron reductive elimination to CuI. Molecular oxygen is also not hampered by toxic byproducts, being either reduced to water, occasionally via H2O2 (oxidase activity), or incorporated into the target structure with high atom economy (oxygenase activity). Such oxidations using oxygen or air (21% oxygen) have been employed safely in numerous commodity chemical continuous and batch processes. 3However, batch reactors employing volatile hydrocarbon solvents require that oxygen concentrations be kept low in the head space (typically< 5− 11%) to avoid flammable mixtures, which can limit the oxygen concentration in the reaction mixture. 4− 6 A number of alternate approaches have been developed allowing oxidation chemistry to be used safely across a broader array of conditions. For example, use of carbon dioxide instead of nitrogen as a diluent leads to reduced flammability. 5 Alternately, water can be added to moderate the flammability allowing even pure oxygen to be employed. 6 New reactor designs also allow pure oxygen to be used instead of diluted oxygen by maintaining gas bubbles in the solvent, which greatly improves reaction rates and prevents the build up of higher concentrations of oxygen in the head space. 4a, 7 Supercritical carbon dioxide has been found to be advantageous as a solvent due its chemical inertness toward oxidizing agents and its complete miscibility with oxygen or air over a wide range of temperatures. 8 A number of flow technologies 9 including flow reactors, 10 capillary flow reactors, 11 microchannel/microstructure reactors, 12 and membrane reactors 13
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影响因子：
3.6
作者：
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通讯作者：
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影响因子：
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DOI：
10.1002/(sici)1099-0518(19991001)37:19
发表时间：
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影响因子：
--
作者：
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通讯作者：
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影响因子：
2.8
作者：
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通讯作者：
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