Ken‐ichi Fujita

[reaction: see text] An efficient catalytic system for oxidant-free oxidation of alcohols has been developed. A new Cp*Ir catalyst bearing a 2-hydroxypyridine ligand has been designed on the concept of "ligand-promoted dehydrogenation". Various secondary alcohols can be dehydrogenatively oxidized to ketones under neutral conditions with high turnover numbers by using the new Cp*Ir catalyst.

[reaction: see text] A new efficient method for the N-heterocyclization of primary amines with diols catalyzed by a CpIr complex was developed. A variety of five-, six-, and seven-membered cyclic amines were synthesized in good to excellent yields with the formation of only water as a byproduct. A two-step asymmetric synthesis of (S)-2-phenylpiperidine was also achieved using (R)-1-phenylethylamine as a starting primary amine.

Homogeneous perdehydrogenation of saturated bicyclic 2,6-dimethyldecahydro-1,5-naphthyridine and perhydrogenation of aromatic 2,6-dimethyl-1,5-naphthyridine with release and uptake of five molecules of H2 are efficiently achieved by iridium complexes bearing a functional bipyridonate ligand. Successive perhydrogenation and perdehydrogenation of 2,6-dimethyl-1,5-naphthryridine using a single iridium complex also proceed with the reversible interconversion of the catalytic species, depending on th

[reaction: see text] A new iridium-catalyzed oxidative cyclization of amino alcohols has been revealed. Indole derivatives are synthesized in good to excellent yields from 2-aminophenethyl alcohols by means of a [CpIrCl(2)](2)/K(2)CO(3) catalytic system. The present catalytic system is also effective for syntheses of 1,2,3,4-tetrahydroquinolines from 3-(2-aminophenyl)propanols and 2,3,4,5-tetrahydro-1-benzazepine from 4-(2-aminophenyl)butanol.

Going into reverse: An efficient and versatile catalytic system for the dehydrogenative oxidation of alcohols under extremely mild conditions has been developed using a Cp*Ir complex with bipyridonate ligand as catalyst (see scheme, Cp*=pentamethylcyclopentadienyl). Reversible and repetitive transformation between 2-propanol and acetone by catalytic dehydrogenation–hydrogenation is also achieved.

An efficient catalytic system for the production of hydrogen from a methanol-water solution has been developed using a new anionic iridium complex bearing a functional bipyridonate ligand as a catalyst. This system can be operated under mild conditions [weakly basic solution (0.046 mol L(-1) NaOH) below 100 °C] without the use of an additional organic solvent. Long-term continuous hydrogen production from a methanol-water solution catalyzed by the anionic iridium complex was also achieved.

A new catalytic system for beta-alkylation of secondary alcohols has been developed. In the presence of [CpIrCl(2)](2) (Cp = pentamethylcyclopentadienyl) catalyst and base, the reactions of various secondary alcohols with primary alcohols give beta-alkylated higher alcohols in good to excellent yields without any hydrogen acceptor or hydrogen donor. This reaction proceeds via successive hydrogen-transfer reactions and aldol condensation. [reaction: see text]

Abstract An efficient and environmentally benign catalytic system for the synthesis of various organic amines catalyzed by the water‐soluble and air‐stable (pentamethylcyclopentadienyl)‐iridium‐ammine iod‐ ide complex, [Cp*Ir(NH 3 ) 3 ][I] 2 (Cp*=pentamethylcyclopentadienyl), has been developed. A wide variety of secondary and tertiary amines were synthesized by the N ‐alkylation reactions of theoretical equivalents of amines with alcohols in water under air without a base. The synthesis of cycl

A new catalytic system for the dehydrogenative oxidation of alcohols using a Cp*Ir complex having a functional C,N-chelate ligand has been developed. With this catalytic system, both primary and secondary alcohols were efficiently converted to aldehydes and ketones, respectively. Mechanistic investigations of this catalytic system have revealed that the catalytically active species is a hydrido iridium complex with a functional C,N-chelate ligand.

A new effective catalytic system consisting of [CpRhCl(2)](2)/K(2)CO(3) (Cp = pentamethylcyclopentadienyl) for the lactamization of amino alcohols has been developed. As an example, the reaction of 3-(2-aminophenyl)-1-propanol in the presence of [CpRhCl(2)](2) (5.0% Rh) and K(2)CO(3) (10%) in acetone gives 3,4-dihydro-2(1H)-quinolinone in an isolated yield of 80%. A variety of five-, six-, and seven-membered benzo-fused lactams are synthesized by this catalytic system. [reaction: see text]

A dicationic iridium complex bearing a bidentate ligand that comprises N-heterocyclic carbene and α-hydroxypyridine moieties has been designed and synthesized. The complex exhibited high catalytic performance in aqueous media for the dehydrogenative oxidation of secondary alcohols to ketones accompanying the evolution of hydrogen. Furthermore, dehydrogenative transformation of primary alcohols to the carboxylic acids in aqueous media was also catalyzed by the complex without using base.

We report a series of arylpalladium complexes of acetamidate, sulfonamidate, and deprotonated oxazolidinone ligands that undergo reductive elimination with rates and yields that depend on the binding mode of the ancillary and amidate ligands. Complexes of the acetamidate ligands containing the bidentate phosphines DPPF and Xantphos as ancillary ligands undergo reductive elimination. The rate and yield were higher from the complex ligated by Xantphos, which contains a larger bite angle. In contra

The C-H bond of benzene was directly arylated by reaction with aryl iodides in the presence of a catalytic amount of a pentamethylcyclopentadienyliridium complex and potassium tert-butoxide.