Naruyoshi Komiya

Ruthenium-catalyzed oxidative cyanation of tertiary amines with molecular oxygen or hydrogen peroxide and sodium cyanide: sp3 C-H bond activation and carbon-carbon bond formation.

Ruthenium-catalyzed oxidative cyanation of tertiary amines with molecular oxygen in the presence of sodium cyanide and acetic acid gives the corresponding alpha-aminonitriles, which are highly useful intermediates for organic synthesis. The reaction is the first demonstration of direct sp(3) C-H bond activation alpha to nitrogen followed by carbon-carbon bond formation under aerobic oxidation conditions. The catalytic oxidation seems to proceed by (i) alpha-C-H activation of tertiary amines by the ruthenium catalyst to give an iminium ion/ruthenium hydride intermediate, (ii) reaction with molecular oxygen to give an iminium ion/ruthenium hydroperoxide, (iii) reaction with HCN to give the alpha-aminonitrile product, H2O2, and Ru species, (iv) generation of oxoruthenium species from the reaction of Ru species with H2O2, and (v) reaction of oxoruthenium species with tertiary amines to give alpha-aminonitriles. On the basis of the last two pathways, a new type of ruthenium-catalyzed oxidative cyanation of tertiary amines with H2O2 to give alpha-aminonitriles was established. The alpha-aminonitriles thus obtained can be readily converted to alpha-amino acids, diamines, and various nitrogen-containing heterocyclic compounds.

Ultrasound-Induced Emission Enhancement Based on Structure-Dependent Homo- and Heterochiral Aggregations of Chiral Binuclear Platinum Complexes

Instant and precise control of phosphorescent emission can be performed by ultrasound-induced gelation of organic liquids with chiral, clothespin-shaped trans-bis(salicylaldiminato)Pt(II) complexes, anti-1. Nonemissive solutions of racemic, short-linked anti-1a (n = 5) and optically pure, long-linked anti-1c (n = 7) in organic liquids are transformed immediately into stable phosphorescent gels upon brief irradiation of low-power ultrasound. Emission from the gels can be controlled by sonication time, linker length, and optical activity of the complexes. Several experimental results indicated that structure-dependent homo- and heterochiral aggregations and ultrasound-control of the aggregate morphology are key factors for emission enhancement.

Aerobic oxidation of alkanes and alkenes in the presence of aldehydes catalyzed by copper salts and copper-crown ether

The oxidation of alkanes to the corresponding alcohols and ketones and the epoxidation of alkenes can be performed efficiently at room temperature with molecular oxygen (1 atm) in the presence of an aldehyde and a copper salt catalyst such as copper(II) hydroxide. Extremely high turnover numbers have been obtained for the oxidation of cyclohexane using a combination of copper(II) chloride and a crown ether as a catalyst.

Highly Phosphorescent Crystals of Vaulted trans-Bis(salicylaldiminato)platinum(II) Complexes

Unprecedented strong phosphorescent emission in the crystalline state is observed for a variety of vaulted trans-bis(salicylaldiminato)platinum(II) complexes which are newly synthesized as a third coordination mode of well-studied bis(salicylaldiminato) complexes. This Communication describes the dynamic photophysical properties of these complexes in the liquid and crystalline states and a mechanistic rationale for the strong emission in the crystalline state.

Metalloporphyrin-Catalyzed Oxidation of Alkanes with Molecular Oxygen in the Presence of Acetaldehyde

The development of an efficient method for the oxidation of unactivated C-H bond of alkanes is of importance from industrial and synthetic points of view. During the course of this study on simulation of the functions of cytochrome P-450 with transition metal complexes, the authors have found the aerobic oxidation systems catalyzed by iron, ruthenium, and copper salts in the presence of aldehydes. Further study revealed that metalloporphyrins bearing meso-pentafluorophenyl groups are highly efficient catalysts for the aerobic oxidation system of alkanes with acetaldehyde.

Aerobic oxidation of alkanes in the presence of acetaldehyde catalysed by copper-crown ether

Abstract Copper-crown ether catalysed oxidation of alkanes with molecular oxygen in the presence of acetaldehyde gives the corresponding ketones and alcohols highly efficiently. High turnover numbers have been obtained for the oxidations of cyclohexane using copper(II) chloride and 18-crown-6 as a catalyst.

Copper complexes for catalytic, aerobic oxidation of hydrocarbons

Catalytic oxidation of hydrocarbons can be performed efficiently upon treatment with tert-butylhydroperoxide or peracetic acid in the presence of a low-valent ruthenium catalyst. Furthermore, aerobic oxidation of hydrocarbons can be performed in the presence of acetaldehyde using ruthenium, iron, and copper catalysts. Copper derived from copper chloride/crown ether or copper chloride/crown ether/alkaline metal salts have proved to be efficient catalysts. Further study revealed that specific copper complexes formed from copper salts and acetonitrile are convenient and highly useful catalysts for the aerobic oxidation of unactivated hydrocarbons.

Ruthenium-catalyzed oxidation of alkanes with peracids

Abstract The ruthenium-catalyzed oxidation of alkanes with peracids under mild conditions gives the corresponding ketones and alcohols highly efficiently. Similar treatment of alkanes in trifluoroacetic acid gives alkyl trifluoroacetates.

New types of catalytic oxidations in organic synthesis

Abstract Simulation of the enzymatic function of cytochrome P -450 with transition metal complex catalysts has resulted in finding biomimetic and catalytic oxidations of amines, amides, β-lactams, alcohols, phenols and hydrocarbons by using ruthenium catalyst and peroxide. Further study revealed that the catalytic formation of peracids in situ from aldehydes and molecular oxygen enables the aerobic oxidation of β-lactams, alcohols, alkanes and ketones in the presence of metal catalyst under mild conditions.

Manganese catalyzed asymmetric oxidation of alkanes to optically active ketones bearing asymmetric center at the α-position

Abstract Chiral (salen)manganese(III) complex catalyzed oxidation of symmetrical alkanes with iodosylbenzene gives the corresponding optically active ketones (up to 70% ee). The optically active 2-hydroxy-1-indanone ( 7 ) thus obtained is a versatile precursor of cis -1-amino-2-indanol ( 8 ) which is a key intermediate of chiral auxiliary and anti HIV protease inhibitor ( 9 ).