AbstractThe design of a versatile alkyne‐bearing derivative of the donor‐acceptor fluorophore 2,4,5,6‐tetrakis(9H‐carbazol‐9‐yl) isophthalonitrile (4CzIPN) suitable for further targeted modifications by copper‐catalysed Azide Alkyne Cycloaddition (CuAAC) is reported. The newly synthesised photoredox catalyst notably exhibits analogously unique photoelectronic and steric features as the well‐established carbazolyl dicyanobenzene motif and performs equally in a C−C‐Coupling model reaction. Furthermore, the variability of this donor‐acceptor system was demonstrated by the generation of a library of fourteen photoredox catalysts with electron‐withdrawing and ‐donating groups as well as residues with high steric demands in one simple and selective CuAAC reaction. The modified catalysts feature a broad scope of reducing and oxidising powers in their excited states (span of reducing powers over more than 1 V) and were also successfully applied in the photoredox and nickel‐catalysed decarboxylative cross coupling model reaction. This work represents a method to overcome the limitations in the flexibility of metal‐free donor‐acceptor fluorophores required for the targeted application in organic synthesis and paves the way for the design of customised catalysts with multiple functionalities.
摘要 报告设计了一种供体-受体荧光团 2,4,5,6-四(9H-咔唑-9-基)异酞腈(4CzIPN)的多功能炔烃衍生物,适合通过铜催化叠氮炔烃环加成(CuAAC)进行进一步有针对性的修饰。新合成的光氧化催化剂与成熟的咔唑基二氰基苯基团一样,具有类似的独特光电子学和立体特征,在 C-Coupling 模型反应中表现出同样的性能。此外,通过在一个简单而有选择性的 CuAAC 反应中生成 14 个带有电子吸收基团和电子供体基团以及具有高立体要求的残基的光氧化催化剂库,证明了这种供体-受体系统的可变性。改性催化剂的激发态具有广泛的还原力和氧化力(还原力跨度超过 1 V),并成功应用于光氧化和镍催化的脱羧交叉偶联模型反应。这项工作是克服无金属供体-受体荧光团在有机合成目标应用中所需灵活性限制的一种方法,并为设计具有多种功能的定制催化剂铺平了道路。