Enyne Metathesis (Part I) and Development of New Methods for Functionalized Arenes (Part II)
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This thesis has two main parts. Part I is composed of two chapters which describe the structure and reactivity of alkyne-chelated ruthenium alkylidene complexes and newly discovered non-metathetic activity of Grubbs catalysts. Part II consists of four chapters describing transition metal-catalyzed new synthetic methods for functionalized arenes via metal-complexed aryne intermediates generated in situ from multiynes. Specifically, in chapter one, recent advances of olefin metathesis are briefly reviewed and the first well-defined alkyne-chelated ruthenium alkylidene is delineated. In chapter two, a brief summary of previously reported notable non-metathetic reactions using Grubbs-type ruthenium alkylidenes is presented and a new 1,4-hydrovinylative cyclization of various multiynes with ethylene using Grubbs type ruthenium alkylidene is discussed. In chapter three, a brief survey for the progress of aryne chemistry and recent computational studies on regioselectivity of nucleophile addition to aryne intermediates is provided. In chapter four, a new paradigm of a catalytic hydrohalogenation to form structurally elaborated aryl halides using ruthenium alkylidene complex is described. In chapter five, a new C-H bond insertion reaction mediated by silver-stabilized arynes generated directly from alkyne building blocks is discussed. Preliminary mechanistic studies to elucidate the reaction mechanism are also presented. Finally, in chapter six a conceptually distinctive method capable of generating Ar-F, Ar-CF3 and Ar-SCF3 from non-aromatic precursors is described. Mechanistic novelty, broad substrate scope and excellent regioselectivity of this method allow an expeditious access to pharmaceutically important functionalized indoline and isoindoline derivatives.
Subjectenyne metathesis Aryne fluorination trifluoromethylation trifluoromethylthiolation Grubbs catalyst alkylidene carbene