April 2023

The development of highly efficient and reusable supported metal catalysts is important for academic and industrial synthetic organic chemistry; however, their widespread application remains a challenge because supported Pd, Rh, and Pt catalysts are expensive. To overcome these problems, we have developed novel, highly stable, reusable, and selective heterogeneous catalysts consisting of silicon nanowire arrays (SiNAs) and metal nanoparticle composites. Metal nanoparticles on SiNA have been applied as heterogeneous catalysts in the Mizoroki–Heck reaction, C–H arylation, hydrosilylation, hydrogenation, reductive alkylation of amines, and hydrogenative decarboxylation of fatty acids. The catalysts used in this study showed high catalytic activity in batch and microflow conditions. Their structural investigation using X-ray Photoelectron Spectroscopy (XPS) suggests that strong metallic bonding (alloy/agglomeration) between the metal and silicon (metal silicide bond formation) is key to the high catalyst stability.1 Introduction2 Development of Silicon Nanowire Array (SiNA) Hybrid Catalysts and Silicon Nanostructure (SiNS) Hybrid Catalysts3 Application of SiNA-Pd to Organic Synthesis4 SINA-Supported Mono- and Bimetallic Nanoparticles for Hydrogenation Reactions5 Application of SiNA-Pd to Microflow Reductive Alkylation Reactions6 Application of SiNA-Rh to Hydrogenative Decarboxylation Reactions using Microwave Irradiation7 Conclusions

Here we present our development of the super Lewis acid, iron(III) triflimide as an activating agent of N-halo- and N-thioaryl succinimides for the regioselective functionalization of arenes. We also describe how the iron(III)-catalyzed halogenation reactions were further exploited by combination with copper(I)-catalyzed Ullmann-type coupling reactions for the development of one-pot, multistep processes, including intermolecular aryl C–H amination. This Account also illustrates intramolecular versions of these one-pot processes for the preparation of benzannulated heterocycles, as well as the application of these methods for the synthesis of biologically active compounds and natural products.1 Introduction2 Iron(III)-Catalyzed Halogenation of Arenes3 One-Pot Intermolecular Aryl C–H Amination4 One-Pot Intramolecular C–N, C–O, and C–S Bond-Forming Processes5 Iron(III)-Catalyzed Thioarylation of Arenes6 Synthesis of Phenoxathiins and Phenothiazines Using Lewis Acid and Lewis Base Catalysis7 Conclusions