Incorporation of Fluorinated Moiety Towards Olefinic Bonds via Multi-Component Reactions

Das, Debabrata (2025) Incorporation of Fluorinated Moiety Towards Olefinic Bonds via Multi-Component Reactions. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Debabrata Das (16IP003)) 16IP003.pdf - Submitted Version Restricted to Repository staff only Download (9MB)

Abstract

The incorporation of fluorinated moieties like CF₃, SCF₃, CF₂-alkyl, perfluoroalkyl, etc., has become a focal point in contemporary organic synthesis and agrochemical research. These fluoro-functional groups bring interesting properties like lipophilic enhancement, transmembrane permeability, and metabolic stability to the modified drugs and bioactive molecules. Driven by a deep interest in fluorination chemistry, our research is dedicated to devising effective methods for functionalizing olefinic structures, widely utilized as reactive sites for diversifying small organic molecules. Photoredox catalysis has quickly gained prominence in organic chemistry research in recent years. This innovative approach leverages a specially designed photocatalyst that harnesses light energy to drive a redox chemical process, easily enabling catalytic chemical transformations. The journey of photocatalysis was initiated with a few well-known metal complexes and organic dyes as an eco-friendly replacement for the expensive transition metal catalysis. Its unique radical mechanism, energy-saving operation, and comparatively mild reaction conditions have contributed to its rapid acceptance. Continuous research has resulted in the development of a variety of new organic photocatalysts, which alleviate both the cost and environmental hazards associated with conventional transition metal complexes of Ir, Ru and with the advancements of variable reactivity and tunability of the catalytic process with plenty of accessible options in organic synthesis. With a keen interest in further developing effective photocatalytic processes for the fluorination of olefinic bonds, we focused on combining multicomponent processes under this radical-mediated reaction pathway. Multicomponent reactions (MCR) are well-known for their step and atom economical, time-saving advantages, and less chemical waste management. Alongside the rich history of classical MCRs, the construction of a photocatalytic radical-mediated MCR is quite challenging. Due to the highly reactive nature of its radical intermediates, they are susceptible to engaging in side reactions resulting in compromised chemoselectivity, byproduct formation, and poor yields. Considering these challenges, a significant research effort for this thesis has been spent on developing various photocatalytic multicomponent reactions, tuning the reactivity of the olefinic unsaturated center for the desired fluorination, and further scope of diversification.

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