三价碘试剂参与的α-亚胺铑卡宾的新反应模式研究

α-Imine rhodium carbene, generated from N-sulfonyl-1,2,3-triazole, has become one of the most important intermediates for the synthesis of nitrogen-containing (heterocyclic) compounds. However, the reaction between α-imine rhodium carbene and electrophile is limited. This project intends to achieve novel reaction modes of α-imine rhodium carbene by investigating the reaction of it with electrophilic iodine(III) reagent: 1) Iodide anion (I-) will be employed as the protecting group of the electrophilic site of the carbenoid carbon, to develop a new reaction mode of α-imine rhodium carbene as 1,3-dipole synthon with electrophilic reagents by multi-catalyst co-catalyzed cascade iodination-electrophilic functionalization-cyclization reactions; 2) Iodine(III) reagent will be engaged as radical source, to develop a new reaction mode of α-imine rhodium carbene as 1,3-diradical synthon by cascade radical addition(-rearrangement)-cyclization reactions. These novel reaction modes will provide new strategies for the synthesis of pyrrole and indole rings, enrich the transformations of α-imine rhodium carbene and bring much deeper understanding of the properties of it, and as well, this project will benefit further studies on the reactions of different metal carbenes with various electrophiles and other radical sources, thus expand the potential of carbene in organic synthesis, especially in the synthesis of nitrogen-containing (heterocyclic) compounds.

由N-磺酰基-1,2,3-三氮唑生成的α-亚胺铑卡宾已经成为了合成含氮（杂环）化合物最重要的中间体之一，但该中间体与亲电试剂的反应却受到限制，反应模式较为单一。本项目拟通过α-亚胺铑卡宾和三价碘亲电试剂的反应，拓展其新的反应模式：1）以I-为卡宾碳亲电位点的保护基，利用三催化剂共催化的碘化-亲电官能团化-环化串联反应，实现α-亚胺铑卡宾作为1,3-偶极合成子与亲电试剂的新反应模式；2）以三价碘试剂为自由基源，利用自由基加成（-重排）-环化串联反应，实现以α-亚胺铑卡宾作为1,3-碳氮双自由基合成子的新反应模式。上述新反应模式将发展新的吡咯和吲哚的合成策略，极大丰富α-亚胺铑卡宾的化学，深化对其性质的理解，为不同的金属卡宾与多种亲电试剂、其他自由基源的反应提供借鉴，拓宽卡宾作为重要的活性中间体在有机合成，特别是含氮（杂环）化合物合成中的应用。

α-亚胺卡宾近年来受到了有机合成化学家的广泛关注，已经成为了合成（氮杂）环状化合物最重要的中间体之一。但其反应模式大多集中于其作为1，3-偶极子参与反应，因此反应模式相对单一，从一定程度上限制了其在有机合成中的广泛应用。本项目利用α-亚胺卡宾的分子内原子（基团）迁移策略，将α-亚胺卡宾发展成为氮杂-[4C]合成子、多活性位点两性离子、α-氰基自由基等活泼中间体，进一步利用这些新型中间体合成了一系列（氮杂）环状化合物及α-氨基酮等，并对产物进行了丰富的衍生化转化；通过较为系统的机理研究，初步阐明了反应的机理。上述工作成功地拓展了α-亚胺卡宾的反应模式，进一步拓宽了α-亚胺卡宾在有机合成中的应用。