Photocatalyzed Activation of C–H Bond of Halogenated Solvents via Hydrogen Atom Transfer Reactions

Sahana, Buddhadeb (2022) Photocatalyzed Activation of C–H Bond of Halogenated Solvents via Hydrogen Atom Transfer Reactions. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS dissertation of Buddhadeb Sahana (17MS210)) 17MS210_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (1MB)

Abstract

Vinylcyclopropanes (VCPs) is a versatile starting material for synthesizing various complex building blocks in natural products, agrochemicals, and pharmaceutical drugs. Several reports imply that VCP is a perfect substrate for synthesizing ring-opening products. Due to its high reactivity, it can easily undergo bond breakage to give various rearrangement products. There are currently a variety of effective directing-group-controlled strategies for catalytic C-H functionalization, which has just recently become a cornerstone of organic chemistry. The development of direct functionalization of alkane C-H bonds using a variety of transition-metal complexes as a catalyst is remarkable. In recent years, photocatalysis for cleaving C–H bonds has become a feasible alternative to thermal methods. The photocatalyst (PC) absorbs light, and the PC in the excited state (PC*) may directly cleave C-H bonds in alkanes via a hydrogen atom transfer (HAT) step, yielding an alkyl radical that can then undergo subsequent radical reactions to form C-H functionalized compounds. This report shows photocatalyzed activation of the C–H bond of halogenated solvent via hydrogen atom transfer. Upon irradiation of sufficiently high energetic photon, if we can activate the C-H bond of halogenated solvents to form its corresponding radical, it could trap by vinyl cyclopropane followed by hydrogen atom transfer to give our halogenated open-chain product. This halogenated product can quickly go through nucleophilic substitution or elimination reaction to give simple nucleophile substituted long-chain derivative or eliminated products.

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