This thesis explores new reactive intermediates and hydrogen atom transfer mechanisms that can be applied to C-N and C-H bond activation. Chapter 1 reviews the current strategies in the literature for C-N bond activation of both primary amine and secondary amines, with a particular emphasis on oxidative deamination, transition metal catalyzed deamination and radical mediated deaminative transformations. Chapter 2 demonstrates a conceptually distinct method for secondary amine activation using an anomeric amide reagent, which involves the conversion of the amine to an isodiazene. Subsequent extrusion of dinitrogen and recombination of the resulting carbon fragments facilitates the net deletion of secondary amines as new method for skeletal editing of organic molecules. Chapter 3 expands the scope of amine deletion using anomeric amides to include primary amines. This deamination proceeds with exquisite functional group tolerance under exceptionally mild conditions, and applications towards late-stage editing of biomolecules are demonstrated. Mechanistic studies demonstrate that this transformation proceeds by a previously unreported isodiazene intermediate which undergoes a novel hydrogen atom transfer chain mechanism. Chapter 4 presents the optimization of a reproducible large-scale synthesis for the anomeric amide reagent and also discusses the modular approach taken to the development of new anomeric amide derivatives. Chapter 5 explores the mechanism of a photoredox-catalyzed C-H arylation reaction using a super-reducing tungsten alkylidyne complex. Experimental studies and DFT calculations provide evidence for a unique proton coupled electron transfer event occurring between the oxidized chromophore and the enyl radical intermediate. A stepwise electron transfer followed by proton transfer and a concerted hydrogen atom transfer are both shown to be operative pathways depending on the reduction potential of the enyl intermediate.