Electrocatalysis in Iodine-based Oxidations

直接利用电能进行化学转化是一种高效、绿色的有机分子活化方式。它避免了昂贵的催化剂和配体，使化学转化成为可能，否则很难实现。由于电子诱导化学反应，因此避免了试剂浪费。通过利用太阳能和风能，可持续电力正变得越来越多。氧化通常需要化学计量的终端氧化剂，有机合成中的许多重要转化都是使用这种方法开发的。在几种情况下，氧化剂的电化学循环是可能的。成功地生成和使用只有催化量的高价碘化合物的关键要求是化学计量氧化剂在底物存在下选择性地生成高价碘化合物的能力。化学计量比的氧化剂必须仔细选择，因为它不能直接与底物反应，而是允许碘化合物的再次氧化。如催化循环的底部所示，这可以通过将碘(I)的水溶液泵入电化学微反应器并反馈被氧化的碘(III)物种来实现。可以调节电化学池中的电流，以便只发生所需的碘(I)到碘(III)的氧化，而不影响衬底。在项目的第二部分，这一方法将扩展到催化生成立体选择性反应的手性碘(III)试剂。学生将以我们在高价碘化学以及流动电化学方面的经验为基础，解决本项目中的挑战。这一极具挑战性的项目将探索将电化学引入催化，然后进一步探索电催化应用的新协同效应。流程方法将是成功的关键，我们将与我们的行业合作伙伴一起，在项目的3.5年内取得重大进展。

The direct use of electrical energy to induce chemical transformations is an efficient and green activation mode of organic molecules. It avoids expensive catalysts and ligands to enable chemical transformations which are otherwise difficult to achieve. Reagent waste is avoided since electrons induce the chemical reactions. Sustainable electricity is becoming increasingly available by exploiting sun and wind energy.Oxidations typically require stoichiometric amounts of a terminal oxidant and many important transformations in organic synthesis have been developed using this approach. Electrochemical recycling of the oxidant is possible in several cases. The key requirement for a successful reaction generating and using hypervalent iodine compounds in only catalytic amounts is the ability of the stoichiometric oxidant to selectively make the hypervalent iodine compound in the presence of the substrate. The stoichiometric oxidant has to be carefully selected as it must not react directly with the substrate but allow the re-oxidation of the iodine compound. This can be achieved by pumping only the aqueous iodine(I) solution through an electrochemical microreactor and feeding back the reoxidised iodine(III) species as shown in the bottom part of the catalytic cycle. The current in the electrochemical cell can be adjusted so that only the desired iodine(I) to iodine(III) oxidation takes place without affecting the substrate. In the second part of the project, this methodology will be extended to the catalytic generation of chiral iodine(III) reagents for stereoselective reactions. The student will build on our experience in hypervalent iodine chemistry as well as flow electrochemistry to address the challenges in this projectThis highly challenging project will explore new synergies in taking electrochemistry towards catalysis and then further to explore electrocatalytic applications. Flow methodology will be key to the success and with our industrial partners we will make major advancements in the 3.5 years of the project.