<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Exploring C−H Functionalization Reactions with Theory and Experiment"^^ . "C−H bond functionalization reactions are powerful, efficient, and potentially step-economic strategy for the construction of carbon−carbon and carbon−heteroatom bonds in organic synthesis. In recent years, novel Ni-catalyzed C−H bond functionalization reactions using N,N bidentate directing groups have been developed to selectively activate inert C−H bonds. However, the reaction mechanisms and origins of reactivity and selectivity of many of these organic transformations remain unclear. A detailed understanding of the molecular processes involved is essential for understanding and developing more efficient and diverse C−H functionalization reactions. Density functional theory (DFT) has emerged as a powerful tool to elucidate reaction mechanisms and intricate details of the elementary steps involved, and divergent reaction pathways in transition metal-catalyzed reactions. In this dissertation, the mechanisms of Ni-catalyzed C–H oxidative annulation, arylation, alkylation, benzylation and sulfenylation with N,N-bidentate directing groups are investigated using DFT calculations. \r\n\r\nNi-catalyzed C–H functionalization reactions can be broadly divided into two distinct mechanistic steps: (i) C–H metalation (ii) C–C or C–heteroatom bond formation steps. Specifically, the C–H metalation may occur via either the concerted metalation-deprotonation (CMD) or σ-complex-assisted metathesis (σ-CAM) mechanism. The subsequent C–C and C–heteroatom bond formation steps may occur via closed-shell Ni(II) or Ni(IV) intermediates. Alternatively, radical pathways involving Ni(III) complexes are also possible. Our studies indicated that the reaction mechanism of Ni-catalyzed C–H functionalization is substrate-dependent. The mechanistic insights gained from the computational studies were employed to investigate a number of experimental phenomena including substituent effects on reactivity, chemo- and regioselectivity, ligand and directing group effects, and the effects of oxidants. \r\n\r\nFurthermore, a novel C(sp3)−H functionalization methodology was developed to synthesize biologically relevant vinyl sulfone-containing compounds of pharmacologically prevalent picolyl amides with allenic sulfones. The reaction conditions are mild. The starting materials can be prepared from readily available sources. The reaction has a broad functional group tolerance. Mechanistic studies suggested that the reaction likely operates via a rare pyridine-initiated and p-toluenesulfinate anion-mediated activation analogous to phosphine-triggered reactions and Padwa’s allenic sulfone chemistry."^^ . "2020-06-08" . . . . . . . . "Humair"^^ . "Omer"^^ . "Humair Omer"^^ . . . . . . "Exploring C−H Functionalization Reactions with Theory and Experiment (PDF)"^^ . . . "Omer Final ETD.pdf"^^ . . . "Exploring C−H Functionalization Reactions with Theory and Experiment (Other)"^^ . . . . . . "lightbox.jpg"^^ . . . "Exploring C−H Functionalization Reactions with Theory and Experiment (Other)"^^ . . . . . . "preview.jpg"^^ . . . "Exploring C−H Functionalization Reactions with Theory and Experiment (Other)"^^ . . . . . . "medium.jpg"^^ . . . "Exploring C−H Functionalization Reactions with Theory and Experiment (Other)"^^ . . . . . . "small.jpg"^^ . . . "Exploring C−H Functionalization Reactions with Theory and Experiment (Other)"^^ . . . . . . "indexcodes.txt"^^ . . "HTML Summary of #38137 \n\nExploring C−H Functionalization Reactions with Theory and Experiment\n\n" . "text/html" . .