Toshio Agawa

Stereoselective synthesis of vinylphosphonate

Abstract Dialkyl vinylphosphonate is stereoselectively prepared by palladium-catalyzed reaction of vinyl bromide with dialkyl phosphite.

Oxidative decarboxylation of α-amino acids with coenzyme PQQ

Abstract Oxidative decarboxylation of α-phenylglycine with coenzyme pqq was performed catalytically in the presence of CTAB under mild conditions to give benzaldehyde and benzoic acid.

Palladium-catalyzed reaction of allylic ammonium bromides with nucleophiles

Abstract The reactions of allylic triethylammonium bromides and dimethylsulfonium bromide with carbon nucleophiles were catalyzed by tetrakis(triphenylphosphine)palladium to afford olefinic esters and ketones.

Micelle enhanced oxidation of amines by coenzyme PQQ

Abstract Nonezymatic oxidation of amines with the coenzyme PQQ is enhanced by a cationic surfactant to give the corresponding carbonyl compounds, suggesting that the micelle presents a good environment for oxidation with PQQ. The similar reaction is applicable to alcohols though an efficiency is not so high.

Reactions of diphenylcyclopropenone with ketenes in the presence of nickel tetracarbonyl

Abstract Reactions of diphenylcyclopropenone with ketenes in the presence of catalytic amounts of nickel tetracarbonyl have been studied. In these reactions, 1 : 1 cycloadducts, cyclopentene-1,2-dione derivatives, were obtained in yields above 80%. The cycloaddition reactions were significantly affected by solvents, and DMF was the most suitable solvent. Iron pentacarbonyl did not act as a catalyst. Reaction mechanisms are discussed.

Versatile synthesis of α, β-acetylenic ketones by oxidative nucleophilic addition of vanadium acetylides

Treatment of aldehydes with vanadium acetylides generated from equimolar amounts of vanadium trichloride and acetylenic Grignard or lithium compounds gave α,β-acetylenic ketones via oxidative nucleophilic addition.

Oxidative nucleophilic addition of organovanadium reagents to aldehydes with formation of ketones

En presence de reactifs de Grignard ou de butyl-lithium les benzaldehydes, furfural, alcanals, enaldehydes reagissent avec VCl 3 , conduisant a des cetones

Synthesis of vinylsilanes by palladium-catalyzed reaction of trimethylsilylallyl acetates with nucleophiles

Abstract Treatment of 1-trimethylsilylallyl and 3-trimethylsilylallyl acetates with nucleophiles (active methylene compounds and enamines) in the presence of a catalytic amount of Pd(PPh3)4 affords vinylsilane derivatives selectively.

Highly chemoselective coupling reactions of organovanadium compounds

Abstract Organovanadium compounds generated in dichloromethane from equimolar amounts of vanadium trichloride and Grignard reagents underwent the chemoselective cross-coupling reaction with acid chlorides leading to the corresponding ketones. Treatment with allyl halides resulted in allylation of organovanadium compounds. In the case of propargyl bromide, regioselective displacement occurred to produce allene derivatives.

New synthesis of pyridone derivative from 1-azadiene

Abstract The reaction of 1-azabutadienes with enolates of substituted acetates gave 3,4-dihydro-2-pyridones which rearrange or dehydrogenate to other isomeric dihydropyridones or pyridones. Thus 1-azabutadienes were found to be good building blocks for pyridone derivatives.