碳氢键的断裂转化具有原子、步骤经济性和环境友好等特点，在药物合成、能源化学等领域具有广阔的应用前景。经典的过渡金属催化的碳氢键活化已取得很大进展，同时也存在着一定的局限性，而自由基引发的碳氢键断裂具有条件温和、选择性好、无需诱导基团等特点。由于可见光具有丰富易得、绿色经济、可再生等特点，因此逐渐受到化学家的重视。另外，氮原子广泛存在于生物活性分子、天然产物和药物分子中，因此实现基于氮原子的碳氢键断裂转化具有重要的实际意义。目前报道的该类自由基催化体系都需要从特殊保护的胺衍生物出发，导致费时费力和局限的底物普适性。基于未保护胺的选择性远程碳氢键断裂转化却非常少见。本研究拟计划通过两个方面来突破这个难题：一是设计合成新的可见光催化剂；二是探索新的反应策略，如小分子气体作为临时诱导基团以及与过渡金属催化相结合等策略，从而可见光催化的对未保护胺及其衍生物的选择性远程碳氢键断裂官能团化。

The direct transformation of inert C-H bond is atom- and step-economic, thus having broad application potential in pharmaceutical science and energy chemistry. Over the past decades, transition-metal catalyzed C-H bond activation has achieved great progress, although with significant limitations. On the other hand, radical initiated C-H bond functionalization is a promising alternative as it is mild, selective and unnecessary to pre-install directing group. Visible light is a green and renewable resource, which is abundant in nature. Recently, visible-light catalyzed reactions via radical process have gained more and more attention from chemical community. Moreover, nitrogen is ubiquitous in bioactive molecules, natural products, and drug molecules. To this end, it is very important to develop the visible-light catalyzed C-H transforming reactions based on nitrogen reactions. The existing catalytic systems are based on amines with specific protecting groups, which require tedious synthetic procedures, thus time- and step-consuming as well as imposing significant limitations on scope. This research proposal plans to overcome the limitations via visible light catalysis: 1) to synthesize and evaluate new photocatalysts; 2) to use new strategies, such as small gas molecules as transient directing and protecting group; homolysis of M-N (M = transition metal ) bond to generate nitrogen radical enabled by the merge of photocatalysis and transition-metal catalysis. By combining above-mentioned strategies, the proposal aims to develop general and practical methods for the selective remote functionalizations of C-H bond of unprotected amines for the construction of new C-C and C-heteroatom bonds.