Ichiro Minami

Ionic Liquids in Tribology

Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

Facile Palladium catalyzed decarboxylative allylation of active methylene compounds under neutral conditions using allylic carbonates

Abstract Palladium catalyzed decarboxylative allylation of active methylene compounds proceeded under mild neutral conditions using allylic carbonates, which are much more reactive than allylic acetates or phenoxides used commonly in the reaction.

Palladium-catalyzed allylation of ketones and aldehydes via allyl enol carbonates

Abstract Rearrangement of allyl enol carbonates, prepared from ketones or aldehydes by trapping their enolates with allyl chloroformate, to give α-allyl ketones or aldehydes regioselectivity is catalyzed by palladium-phosphine complexes under mild conditions.

Reactions of allylic carbonates catalyzed by palladium, rhodium, ruthenium, molybdenum, and nickel complexes; allylation of carbonucleophiles and decarboxylation- dehydrogenation

Abstract Allylation of carbonucleophiles with allylic carbonates catalyzed by various transition metal complexes has been studied. Palladium, rhodium, ruthenium, nickel, and molybdenum complexes were found to be active catalysts. The rhodium catalyst showed a different regioselectivity from the other catalysts, the reaction can proceed without allylic rearrangement. In the absence of nucleophiles, allyl alkyl carbonates were converted into ketones by decarboxylation-dehydrogenation; the ruthenium catalyst was the most active in this reaction.

A new furan annelation reaction by the palladium-catalyzed reaction of 2-alkynyl carbonates or 2-(1-alkynyl)oxiranes with β-keto esters

Abstract A new furan annelation by the palladium-catalyzed reaction of 2-alkynyl carbonates with β-keto esters is described. The reaction proceeds under mild neutral conditions and hence unstable 3-alkylidene-2,3-dihydrofurans can be prepared in this way. Similarly, reaction of 2-(1-alkynyl)oxiranes with β-keto esters gives alkylidene furans.

New synthetic methods for α,β -unsaturated ketones, aldehydes, esters and lactones by the palladium-catalyzed reactions of silyl enol ethers, ketene silyl acetals, and enol acetates with allyl carbonates

Abstract Silyl enol ethers and ketene silyl acetals derived from ketones, aldehydes, esters and lactones are converted into α,β-unsaturated ketones, aldehydes, esters and lactones by treatment with allyl carbonates in high yields using the palladium—bis(diphenylphosphino)ethane (dppe) complex as catalyst. Phosphine-free palladium catalyst instead of the palladium—phosphine complex gives a higher selectivity for the preparation of cyclopentenone, cyclooctenone, dienones, α,β-unsaturated esters and lactones. As a solvent, the use of nitriles such as acetonitrile is essential. In other solvents, allylation takes place. Enol acetates derived from ketones are converted into α,β-unsaturated ketones by reaction with allyl carbonate in acetonitrile using the palladium complex and tributyltin methoxide as bimetallic catalysts.

Palladium-catalyzed carbonylation of propargylic carbonates: Preparation of 2,3- and 2,4-dienyl carboxylates

Summary Propargylic carbonates are converted to 2,3-dienyl carboxylates by the palladium-catalyzed decarboxylation-carbonylation in alcohol under mild conditions. In ether, 2,4-dienyl carboxylates are obtained.

Palladium-catalyzed reaction of allyl carbamates; allylation of carbonucleophiles, and protection-deprotection of amines

Abstract Allylation of carbonucleophiles with allylic carbamates under neutral conditions has been studied. The C-allylation of carbonucleophile is competitive with the N-allylation of amines, and the structure of amines is crucial for the selectivity. Bulky secondary amines gave the best results. Also a new method of protection-deprotection of amines as carbamates has been developed. Smooth deprotection is possible by the palladium-catalyzed reaction of allyl carbamates with formic acid. This method is particulary useful for primary amines, including optically active amino acids.

Allyation of carbonucleophiles with allylic carbonates under neutral conditions catalyzed by rhodium complexes

Abstract Rhodium-phosphine complexes catalyze the allylation of carbonucleophiles with allylic carbonates under neutral conditions. In addition, we found unusual regioselectivity in the rhodium catalyzed allylation.

A novel palladium-catalyzed preparative method of α,β-unsaturated ketones and aldehydes from saturated ketones and aldehydes via their silyl enol ethers

Abstract Silyl enol ethers prepared from saturated ketones and aldehydes can be converted to α,β-unsaturated ketones and aldehydes by the reaction of allyl carbonate in the presence of palladium-phosphine complexes as a catalyst. The selection of solvent is crucial and nitriles are most effective as the solvent.