Studies On Ring-Opening Metathesis Polymerization Catalyzed By Hydride Containing Mono-and Di-nuclear Ruthenium Complex And C-H Bond Activation Catalyzed By Group8Transition Metals

Ring-Opening metathesis polymerization (ROMP) has emerged as an important tool for the preparation of architecturally unique macromolecules from cyclic olefins. We wish to report on the development of a series of catalytic systems, afforded by Ru complexes and amine borane adducts, for the ROMP of norbornene. In particular, a two-component system,[Ru(p-cymene)Cl2]2(Cl)/BH3·Me3, can be used for the ROMP of norbornene at60℃. Structural modification of a key complex isolated from the two-component mixture,[RuCl(p-cymene)]2(μ-H)(μ-Cl)(C2), through the abstraction of chloride ligand and incorporation of hydride bridge ultimately leads to the elaboration of a system with room temperature ROMP activity. The hydride ligand is critical based on its high trans effect (for ligand dissociation) and the ability to generate carbene species through plausible migratory insertion and a-elimination steps.Catalytic C-H functionalization has emerged as a valued atom and step-economical strategy for the elaboration of organic molecules. And N-nitroso compounds are a versatile class of organic structures that allow expedient access to a diversity of synthetically useful architectures through demonstrated reactivities. We wish to disclose a Rh(Ⅲ)-catalyzed cyclization of N-nitrosoanilines with Ethyl glyoxylate for streamlined synthesis of a-hydroxyl carboxylic ester in Chapter Three. Noteworthy is the tolerance of a broad range of auxiliary functional groups, thus potentially permitting predefined, programmable substitution patterns to be incorporated into the a-hydroxyl carboxylic ester scaffold. Comprehensive mechanistic studies on kinetic isotope effect (KIE), electronic effect, intermediate interception have allowed the key set of catalytic elementary steps to be delineated. The a-hydroxyl carboxylic ester with N-Nitroso group can be transformed to3-hydroxyl oxindole under either mild Raney Ni/H2or NH2SO3H/HCI conditions. And this a-hydroxyl carboxylic ester with N-nitroso group was also transformed to indazoles with the base t-BuOK. This ability to elaborate the N-nitroso moiety to other functionality provides a seminal example of the innumerable synthetic possibilities offered by this transformable directing group. Besides, in Chapter Four, we report on the attempt of an N-nitroso directing group method with other transition metal-catalyzed C-H olefination or alkylation of arenes (Ru, Pd, Ir).[Ru(p-cymene)Cl2]2and Pd(OAc)2cannot catalyze the alkylation or olefination of the subtrate bearing N-nitroso group. And the cyclopalladated N-methyl-N-nitrosoanilines [Pd(μ-OAc){ONN(CH3)(C6H4)}]2can not react with olefin or alkyne, but can react with phenylboronic acid affording the coupling product. When using [Ir(OMe)(COD)]2as catalyst the N-nitroso group act as steric factor rather than directing group in the borylation reaction between the substrate and a diboron reagent B2pin2(Bis(pinacolato)diboron).The direct catalytic activation and functionalization of alkanes to introduce valuable synthetic groups has long been a challenging area of investigation in both organometallic and synthetic organic chemistry. In Chapter Five, we report that borylation of the unactivated C(sp3)-H bonds of cyclooctane using4,4,5,5-tetramethyl-1,3,2-dioxaborolane (HBpin) with CoCl(PPh3)3or CoBr2as catalyst.