Studies Toward Chelation Assisted Ortho-Selective C-H Bond Functionalization of Arenes
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The chapter 1 describes the literature survey of the transition-metal-catalyzed cross-coupling, C-H activation, chelation-assisted C-H functionalization and their mechanisms. Chapter 2 demonstrates Pd-catalyzed ortho-halogenation of N-aryl ring of N,1-diphenyl-1H-tetrazol-5-amines via chelation assisted C-H functionalization utilizing N-halo succinimide (NXS) as halogen source and CF3SO3H as an additive at moderate temperature. Chapter 3, presents a room temperature Cu-catalyzed chemo- and regioselective nitration of arenes using Fe(NO3)3∙9H2O as a nitro source. Here, 5-aminotetrazole and 3-amino-1,2,4-triazoles serve as the chelating groups. The directing group can be cleaved to give 2-nitroanilines in good yields. The mechanistic aspects have been illustrated based on kinetic isotope studies, ESI-MS and radical scavenger experiments. Chapter 4, focuses on Cu-mediated regio-selective cross-dehydrogenative coupling (CDC) approach for the N-arylation of azoles under basic conditions. The reaction of pyrroles, indoles, pyrazoles and carbazole has been included. The kinetic studies show that the C-H bond cleavage takes place in the rate determining step.
Supervisor: T Punniyamurthy