Catalytic Reactions of Ruthenium, Copper Nanoparticles and Rhodium Homogeneous Catalysts

Abstract

Transition metal-catalyzed catalytic reaction is one of the most fundamental processes to construct the chemical structure. Depending on the type of transition metal catalysts, the catalytic reactivity is quite different. In the field of heterogeneous catalysts, nanoparticle catalysts have been attracted due to their unique reactivity and relatively simple process for reuse. Homogeneous catalysts have many advantages such as high reaction rate and selectivity to achieve catalytic reaction of fine chemicals. Thus, developing a unique catalytic reaction with transition metal catalysts is essential to expand the field of synthetic methods. This dissertation describes the development of catalytic reaction of transition metal nanoparticles and rhodium compounds. We discovered that ruthenium nanoparticle on non-activated charcoal is quite effective for constructing azobenzen derivatives which are useful materials of dyes and pigments. Furthermore, instead of hydrogen gas, ethanol is used as a hydrogen source. Three different products derived from nitroarene derivatives were obtained by changing the amount of ethanol. Copper is abundant and inexpensive metal than ruthenium metal. Using commercially available copper nanoparticles as a catalyst, cross-coupling reactions between alkyl halides with Grignard reagents were studied. The cross-coupling reaction did not require any phosphine or amine ligands and proceeded smoothly at room temperature. In particular, quaternary carbon center, being difficult to synthesize, was established in the presence of copper nanoparticle and tertiary alkyl Grignard reagents. Alcohol is one of the most common organic compounds in our lives. It is often used as a polar solvent in chemical reactions. As mentioned above, alcohol can be employed as a hydrogen source. In addition, the role of alcohol can be extended to a carbon monoxide surrogate, a hydride-donor, and a nucleophile in the presence of rhodium catalysts. In the synthesis of esters from aryl iodides and alcohols in the presence of a rhodium catalyst and a base, an alcohol acted as carbon monoxide and nucleophile. Alcohol acted as a hydride source to form a rhodium hydride intermediate and a carbon monoxide surrogate in intermolecular carbonylative cycloaddition reactions with alkyne.