Research Projects

Metalloradical catalysis (MRC) involves the generation of metal-bound carbenes or metal-carbenoid intermediates through the activation of carbene precursors from metalloporphyrin-based catalysts, followed by radical addition or radical abstraction to achieve a versatile range of important organic transformations such as olefin cyclopropanation, cyclopropenation, aziridination, bicyclization, etc. Metal complexes generated via MRC can control reactive radical intermediates, enabling unique and efficient catalytic transformations by the transfer or sharing of a single electron in a stepwise manner, solving the inherent challenges associated with the control over reactivity and selectivity in radical chemistry. Even though ionic chemistry has dominated the formation of organic compounds via heterolytic two-electron bond formation and cleavage, radical chemistry presents several attractive features, such as faster reaction rates, milder and neutral reaction conditions, and reduced sensitivity towards electronic and steric properties of substrates, provided we can control the reactivity and selectivity of radical intermediates. Metalloradical catalysis has emerged as a new and innovative way of dealing with one-electron chemistry. To date, limited organic compounds are used as carbene precursors, such as halocarbons, hydrazones, and diazo ylides. The carbene generation from these compounds requires harsh conditions, such as a highly basic environment and high temperatures. Apart from these, they are unstable, toxic, and explosive in nature, which makes them challenging to work with. The above-mentioned disadvantages make them less reliable for a sustainable approach to organic synthesis. Diazo compounds have been frequently utilized as the primary precursors for carbenes in metalloradical chemistry. Therefore, there is a strong inclination toward replacing these compounds with alternatives that offer greater stability and reduced hazards. Hypervalent iodine (HVI) compounds, which have a significant electronegativity difference in carbon and iodine and help them exist in a zwitterionic nature, have emerged as safer and greener alternatives due to their similar reactivity to heavy metals and environmentally benign, less toxic nature. Iodonium ylides fall into the iodine(III) class of HVI compounds and can act as free carbene sources and carbenoid precursors in the presence of various metal catalysts but remain largely unexplored in MRC. Further, they can be classified into cyclic and acyclic types, and they can show varied reactivity under different catalytic systems. Most catalysts employed in MRC to date are air sensitive and demand inert reaction conditions. Therefore, there is a need to develop air-stable catalysts to perform these types of reactions. Porphyrin ring electronics, due to their electron-withdrawing or electron-donating substituents, play a significant role in metal-porphyrin complexes to make them proficient catalysts. Importantly, the reactivity of metal-porphyrin catalysts can be further tuned by insight-driven screening through computational investigations. We aim to develop a modular strategy to utilize iodonium ylides as a potential carbene precursor in metalloradical catalysis for transformations such as olefin cyclization, dihydrofuran, furan, oxazole, and skipped diene formation using air-stable Fe-porphyrin-based catalysts under mild reaction conditions. Additionally, computational methods are set to be utilized to refine our approach towards the optimal catalytic system and substrate modifications necessary to carry out these reactions and decipher the underlying mechanism associated with these transformations.