NON-PRECIOUS METAL CATALYSED (DE)- HYDROGENATION STRATEGIES: DIRECT ACCESS TO NHETEROCYCLES, GEM BIS-SUBSTITUTED KETONES, AND ARYL ACETONITRILES

Abstract

Dehydrogenation is a fundamental organic reaction, where the abstraction of adjacent hydrogen takes place to form a reactive substance. However, the overall reaction process is endothermic in nature. Due to the thermodynamic unfavourability of the reaction, some sort of exogenous activation is needed. To achieve effective transformations, chemists utilized stoichiometric amounts of oxidant and such processes are well studied in conventional techniques. However, such processes produced a large quantity of hazardous waste. So, to develop more sustainable strategy, where hydrogen gas can be generated as a by-product a wise combination of catalytic system is needed. As we all know, hydrogen gas can be utilized as a power source, or it can be utilized as fertilizer in the agrochemical industry, but storage of hydrogen gas associated with few challenges and high-pressure vessel are required. In another approach, the in-situ generated hydrogen gas can be utilized further towards various organic transformations. If another nucleophile is introduced in the reaction system, then it could end up with different products. One such kind of methodology is Acceptorless Dehydrogenation (AD) where the dehydrogenated product further undergoes nucleophilic addition with the other nucleophile, and hydrogen gas is produced as a by-product. More specifically, in situ generated hydride or hydrogen atom borrowed by metal can be given back in one-pot operation. This technique involved in several bond breaking and bond constructions processes, which is difficult to achieve otherwise. Overall strategy known as Hydrogen-borrowing methodology (HB) or Hydrogen Auto-transfer process. These catalytic strategies were investigated thoroughly and applied to activate and functionalize small molecules throughout my doctoral research.