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A methodology for the high yield and facile synthesis of isoquinolones from benzamides and alkynes via the oxidative ortho C−H activation of benzamides has been developed. Ag2CO3 proved to be an optimal oxidant when MeCN was used as a solvent, and [RhCp*Cl2]2 was utilized as an efficient catalyst. Both N-alkyl and N-aryl secondary benzamides can be applied as effective substrates. Furthermore, primary benzamides react with two alkyne units, leading to tricyclic products via double C−H activation and oxidative coupling. The reactivity of the structurally related 1-hydroxyisoquinoline was also demonstrated, where both N- and O-containing rhodacyclic intermediates can be generated, leading to the construction of different O- or N-containing heterocycles.

In this dissertation, my aim is to study different type of under-explored N-Heterocyclic Carbenes (NHC) complexes of Ir and Rh. These complexes have been synthesized, and the reaction mechanism, solution dynamics, and catalytic activity studies are presented in this dissertation. In Chapter 2 shows that phosphine-tethered imidazolium ions can undergo C-H oxidative addition when treated with [Ir(COD)Cl]2 to give abnormal iridium(III) NHC hydrides. The effects of the length of the linker, the kinetic studies of C-H activation and catalytic application of these complexes are systematically studied. Chapter 3 describes the synthesis of iridium and rhodium complexes stabilized by 2-methyleneimidazoline ligands via highly selective intramolecular activation of 2-methyl C-H vs C4/5-H bonds of the imidazolium moieties with the chelation assistance of phosphine ligands. The selectivity of C(sp3)-H vs C(sp2)-H activation, the conversion of methyleneimidazoline to abnormal complex and the electronic properties of ligands are also presented. DOCTOR OF PHILOSOPHY (SPMS)

A new type of quinoline-functionalized palladium N-heterocyclic carbene (NHC) complexes has been synthesized via silver transmetallation. The quinoline moiety was either directly attached to the imidazole ring or linked to it by a methylene group. NHCs with a methylene linker tend to form trans biscarbene complexes in the reaction of Pd(COD)Cl2, while NHCs without any linker form chelating NHC-quinoline (NHC-N) complexes. These two types of carbenes also react with [Pd(allyl)Cl]2 to give monodentate NHC palladium eta(3)-allyl chlorides [Pd(NHC)(allyl)Cl]. Fluxionality in the NMR time scale was observed for most complexes, and the origin of their dynamic behaviors was discussed for each type of structure. For [Pd(NHC)(allyl)Cl] with a relatively small wing tip group of the NHC, the fluxionality (selective line-broadening of (1)H NMR signals) is caused by selective eta(3)-eta(1)-eta(3) allyl isomerization. For NHC with a bulkier (t)Bu group, a different line-broadening pattern was observed and was ascribed to partially hindered Pd-C(carbene) bond rotation. For cationic chelating complexes [Pd(NHC-N)(allyl)]BF4, the dynamic exchange process likely originates from a dissociative boat-to-boat inversion of 7-membered palladacycles. Activation parameters were measured for this process. Crystal structures were reported for representative complexes in each category.

Ir(I)-induced tautomerization of a pyridine moiety to a carbene in 2,3-bipyridyls has been successfully achieved where an amide group plays a key role as a hydrogen-bonding acceptor and the carbene tautomer is stabilized by both chelation effect and by hydrogen-bonding.

An efficient one‐pot four‐component coupling process for the synthesis of polyhydroquinoline derivatives catalyzed by montmorillonite K10 clay is described. This procedure has such advantages as short reaction time, high yields, and simple workup. The catalyst could be reused several times and keeps its initial activity in the recycle reactions.

Fe3+‐montmorillonite clay catalyst was used for the first time for pyrroles preparation by Paal–Knorr condensation. The features of this catalytic system are improved yields, mild conditions, a simple procedure, and high catalytic efficiency. The catalyst could be easily recycled and reused for three times without visible losing of activity.

Rhodium(III)-catalyzed direct functionalization of C-H bonds under oxidative conditions leading to C-C, C-N, and C-O bond formation is reviewed. Various arene substrates bearing nitrogen and oxygen directing groups are covered in their coupling with unsaturated partners such as alkenes and alkynes. The facile construction of C-E (E = C, N, S, or O) bonds makes Rh(III) catalysis an attractive step-economic approach to value-added molecules from readily available starting materials. Comparisons and contrasts between rhodium(III) and palladium(II)-catalyzed oxidative coupling are made. The remarkable diversity of structures accessible is demonstrated with various recent examples, with a proposed mechanism for each transformation being briefly summarized (critical review, 138 references).

[RhCp*Cl(2)](2) can catalyze the oxidative coupling of secondary isonicotinamides with activated olefins using Cu(OAc)(2) as an oxidant. The selectivity can be controlled by the solvent. In MeCN, the mono-olefination and two-fold oxidation reaction is the major pathway, while in THF this reaction gave mostly diolefination products. In both cases, the coupled products contain an exocyclic C=C bond.