Re-Inventing Olefin Oxidation Using Visible-Light Photocatalysis

烯烃是从石油和植物生物质中容易获得的原料，在制备高价值材料中起着不可或缺的作用。特别是，氧化反应用于在烯烃碳上引入氧原子，从而将这些分子转化为广泛的合成中间体，如醛、酮、醇和羧酸。烯烃氧化通常使用臭氧分解反应进行，臭氧分解反应主要用于散装化工，在结构简单的材料上可以进行安全且大规模的工艺。精细化工部门（制药和农用化学工业）不使用这种反应性，因为它们的底物很复杂，含有脆弱的功能。这意味着仍然需要多步骤方法来克服这一合成挑战。一种新的化学策略的发明能够实现烯烃构建块的一般和选择性氧化，对于促进和简化对我们社会至关重要的分子的鉴定和制备具有战略意义。本提案的总体目标是开发可见光介导的光化学反应的第一个例子，使烯烃构建块的氧化裂解产生醛和酮。通过这种方式，我们将提供一种独特的反应，能够简化目前难以制备但受到制药和农化发现计划高度追捧的含o片段的合成。-我们的目标是使用简单的硝基芳烃，这是一种每年以多吨规模生产的大型原料，作为光活性氧化剂与可见光和光催化剂的结合。该策略将探索硝基芳烃通过直接能量转移进行光激发到三重态的能力。然后，这些物质会与烯烃发生新的自由基[3+2]型环加成反应，形成一类新的杂环。由该反应形成的物质可以有效地认为是n掺杂的臭氧化物，并将在C-C键上进行快速裂解，从而导致氧化材料。-我们将进行详细的机理研究，以充分了解三硝基芳烃的活化过程和反应性。-然后，我们将对这种反应性进行基准测试，以实现越来越复杂和功能化的烯烃构建块的氧化。我们的目标是准备一个大型的硝基芳烃文库，以评估它们的三重态反应性。这可能使鉴定试剂能够选择性地区分基于空间或电子因素的烯烃。总体而言，该项目将为烯烃的快速、选择性和温和氧化开发一种创新策略。获得这些高价值材料的可能性将促进治疗剂和农用化学品的发现、开发和制造，对英国社会的福祉产生全面影响。

Olefins are feedstocks readily available from petroleum and vegetable biomass with an integral role in the preparation of high-value materials. In particular, oxidation reactions are used to introduce oxygen atoms across the olefin carbons and thus convert these molecules into a broad spectrum of synthetic intermediates like aldehydes, ketones, alcohols and carboxylic acids.Olefin oxidation is generally performed using the ozonolysis reaction which is mostly adopted by the bulk chemical industry where safe and large-scale processes on structurally simple materials are possible. The fine chemical sector (pharmaceutical and agrochemical industries) do not use this reactivity as their substrates are complex and contain fragile functionalities. This means that multi-step approaches are still required to overcome this synthetic challenge. The invention of a new chemical strategy able to achieve the general and selective oxidation of olefin building blocks is of strategic importance to facilitate and streamline the identification and the preparation of molecules critical to our society.The overarching aim of this proposal is to develop the first example of a visible-light-mediated photochemical reaction enabling the oxidative cleavage of olefin building blocks to produce aldehydes and ketones. In this way, we will provide a unique reaction able to streamline the synthesis O-containing fragments currently difficult to prepare but highly sought after by pharmaceutical and agrochemical discovery programs.- We aim to use simple nitro-aromatics, a large class of feedstocks produced annually on multi ton-scale, as photoactive oxidants in combination with visible-light and a photocatalyst. This strategy will explore the ability of nitro-arenes to undergo photoexcitation to their triplet state by direct energy-transfer. These species will then engage in novel radical [3+2]-type cycloadditions with olefins to give a new class of heterocycles. The species formed by this reaction can be effectively considered as N-doped ozonides and will undergo fast cleavage across the C-C bond thus leading to the oxidised materials.- We will run detailed mechanistic studies to fully understand the activation process as well as the reactivity of triple nitro-arenes.- We will then benchmarke this reactivity to achieve the oxidation of progressively more complex and functionalised olefin building blocks. We aim to prepare a large library of nitro-aromatics to evaluate heir triplet state reactivity. This might enable the identification of reagents able to selectively discriminate between olefins based on steric or electronic factors. Overall, this project will develop an innovative strategy for the fast, selective and mild oxidation of olefins. The possibility to access these high-value materials will facilitate the discovery, development and manufacture of therapeutic agents and agrochemicals with overall impact to the well-being of UK society.