Synthesis of Amides and Amines via Catalytic Activation of Alcohols Using Ruthenium and Iridium Complexes

Abstract

The research described in this thesis covers the development of new eco-friendly and atom-economic synthetic methods for C–N bond formation based on the transition-metal-catalyzed activation of alcohol. This study focused on the synthesis of synthetically and industrially valuable molecules such as amides and amines. Along with the great importance of the alcohol activation strategy, the basic concepts and the corresponding state-of-the-art reactions are explained in Chapter 1. Efficient synthesis of amides from alcohols and azides, a new alternative nitrogen source, using the alcohol activation strategy is described in Chapter 2. The amide synthetic method utilizing stable, easy-to-handle, and readily available starting materials is highly desirable. Our developed method presents the first example of amide synthesis starting from alcohols and azides via the Ru-catalyzed dehydrogenation of alcohol-in situ reduction of azides. Amides and secondary amines were synthesized from esters and primary amines for the first time using a commercially available Ir catalytic system as described in Chapter 3. Two important C–N bonds were obtained in one-pot sequential reactions via amidation and borrowing-hydrogen method. This method provides an efficient way to utilize an ester group using the removed alcohol as the next carbon source after the amidation. These synthetic protocols generate hydrogen or water as the non-harmful by-products, satisfying the concept of sustainable chemistry. The developed methods expand the synthetic versatility and efficiency of amide and amine bond formation. In the final part of this study, as a parallel concept to sustainable chemistry, a series of immobilized olefin metathesis catalysts were prepared (Chapter 4). Vinyl sulfonamide-based ligands were synthesized, and the ligands and silane groups were successfully linked via carbamate to immobilize the ligands on silica. The catalytic activities of these heterogeneous Ru catalysts for ring-closing metathesis were evaluated. The catalysts could be effectively removed from the reaction mixture.