Palladium-catalyzed aerobic oxidation reactions have been the focus of industrial application and extensive research efforts for nearly 60 years. A significant transition occurred in this field approximately 20 years ago, with the introduction of catalysts supported by ancillary ligands. The ligands play crucial roles in the reactions, including promotion of direct oxidation of palladium(0) by O2, bypassing the typical requirement for Cu salts or related redox cocatalysts to facilitate oxidation of the reduced Pd catalyst; facilitation of key bond-breaking and bond-forming steps during substrate oxidation; and modulation of chemo-, regio-, or stereoselectivity of a reaction. The use of ligands has contributed to significant expansion of the scope of accessible aerobic oxidation reactions. Increased understanding of the role of ancillary ligands should promote the development of new synthetic transformations, enable improved control over the reaction selectivity, and improve catalyst activity and stability...

Ligand-Promoted Palladium-Catalyzed Aerobic Oxidation Reactions

Homogeneous catalysis with transition metal complexes containing sulfur ligands

Mixed cyclopentadienyl/dithiolene complexes

Steric Influence on the Reactivity of the (o-Carboranedithiolato)iridium(III) Complex [Ir(η5-C5Me5)(η2-S2C2B10H10)]: New Types of Addition Reactions Involving Cyclometalation or Isomerization†

The syntheses and unique chemical properties of metalladithiolene rings (especially in [CpM(S2C2R1R2)]-type complexes) found by our research group are reviewed. The constructions of metalladithiolene rings by one-pot reaction among [CpM(CO)n], alkyne, and elemental sulfur and by the reaction between [CpM(CO)n] and sulfur-containing heterocyclic compounds are described. Several ionic and radical substitution reactions are presented. The substitutions by carbon-centered and sulfur-centered radicals occur in the metalladithiolene rings. Benzoyloxy-substitution by dibenzoyl peroxide (BPO) and succinimido-substitution by N-halosuccinimides (NXS) proceed via ionic mechanisms induced by the heterolysis of BPO and NXS in the interaction with the lone pair electrons at the sulfur atoms. These substitutions are due to the aromatic character of the metalladithiolene rings. The unique addition reactions due to the unsaturated character of the metalladithiolene rings are also described. Diazo compounds and azides reac...

Synthesis and Chemical Properties of Metalladithiolene and Metalladithiazole Rings. Unique Reactions Due to Coexistence of Aromaticity and Unsaturation

Electrophilic and Radical Substitution of 1,2,5-Cobaltadithiolenes

Adduct between quadricyclane and (η5-cyclopentadienyl)(1,2-benzenedithiolato)cobalt(III): formation and structure

Formation, structure, and reactivities of 1:1 adducts between quadricyclane and (η5-cyclopentadienyl)(1,2-diphenyl- or -dimethoxycarbonyl-1,2-ethenedithiolato)rhodium(III)

Isomerization of quadricyclane to norbornadiene catalysed by (η5-cyclopentadienyl)(substituted 1,2-benzenedithiolato)cobalt(III) complexes

Photochemical reactions of several adducts of metalladithiolenes and metalladithiazoles---dissociation and rearrangement--

Tetsuji Fujita

Papers

Electrophilic and Radical Substitution of 1,2,5-Cobaltadithiolenes

Adduct between quadricyclane and (η5-cyclopentadienyl)(1,2-benzenedithiolato)cobalt(III): formation and structure

Formation, structure, and reactivities of 1:1 adducts between quadricyclane and (η5-cyclopentadienyl)(1,2-diphenyl- or -dimethoxycarbonyl-1,2-ethenedithiolato)rhodium(III)

Isomerization of quadricyclane to norbornadiene catalysed by (η5-cyclopentadienyl)(substituted 1,2-benzenedithiolato)cobalt(III) complexes

Photochemical reactions of several adducts of metalladithiolenes and metalladithiazoles---dissociation and rearrangement--