Tetsuo Hino

Synthesis of aromatic polyketones by using biphenylene monomers

Bisfunctional biphenylene monomers were designed, synthesized, and inspected as building blocks for aromatic polyketone synthesis. Starting from 2,2′-dimethoxybiphenylene (1), a highly activated acyl-acceptant biphenylene monomer affording high molecular weight polyketones, two types of biphenylene monomers were developed: 5,5′-bis(3[4]-chlorobenzoyl)-2,2′-dimethoxybiphenylenes (6) which readily gave the corresponding polyketones by nickel-catalyzed aromatic coupling polymerization and 2,2′-bis(trifluoromethyl)-4,4′-biphenylenedicarboxylic acid (27) which reacted with biphenylene 1 in P2O5CH3SO3H to give the corresponding fluorinated aromatic polyketone, selectively. The related model reactions for both monomer synthesis and polymerization were also investigated.

Synthesis and transformation of a novel methano[60]fullerene having a formyl group

The reaction of [60]fullerene with a dimethylsulfonium α-formylalkylide gave a novel methano[60]fullerene having a formyl group at the bridge-head carbon. This 2,2-[60]fulleroalkanal was readily converted into a variety of N-aryl-2,2-[60]fulleroaldimines by condensation with aromatic amines; one of them showed efficient quenching of the fluorescence of the [60]fullerene core, due to a photoinduced intramolecular electron transfer.

Structural requirements for decarbonylative α,α-diarylation reaction of 2-methoxyalkanoic acids in phosphorus pentoxide-methanesulfonic acid mixture yielding 1,1-diarylalkane homologs

Abstract 2-Methoxyalkanoic acids were found to undergo consecutive decarbonylative α,α-diarylation in P 2 O 5 -MsOH instead of Friedel-Crafts type arylation on the carbonyl carbon. The influence of the substituents of the arenes and the carboxylic acids in this reaction was elucidated based on the reaction yields. The reaction behavior was found to be primarily governed by the electron-withdrawing/releasing property of the α-substituents on the carboxylic acids as well as the positive species-accepting ability of the arenes. The steric hindrance was shown to participate in determining the reaction feasibility as a secondary factor.

Synthesis of 3-Trifluoromethyl-4-halobenzonitriles

Abstract The practical synthetic method for a series of substantially novel fluorine-containing polyfunctional aromatic compounds, 3-trifluoromethyl-4-halobenzonitriles [halo = Cl, Br, and F], was established by using copper-cyano complexes as effective Sandmeyer cyanating reagents.

Acid-Mediated Specific α,α-Diarylation And A-Monoarylation Reactions Of Pyruvic Acid With/Without Decarbonylation

Abstract Pyruvic acid (3) was found to be arylated chemoselectively at the a-ketocarbonyl carbon in P2O5-MsOH affording decarbonylative α,α-diarylated products 5, decarbonylative a-monoarylated compounds 6, or non-decarbonylative α,α-diarylated adducts 7 depending on the reactivity of arenes (4a-g), in contrast to Lewis acid-catalyzed reaction of its acid chloride (2).

Synthesis of methano[60]fullerene derivatives: the fluoride ion-mediated reaction of [60]fullerene with silylated nucleophiles

A new reaction of [60]fullerene with silylated nucleophiles is described. The cyclopropanation of [60]fullerene with silylated nucleophiles, such as silyl ketene acetals, silyl ketene thioacetals, and silyl enol ethers, derived from α-halo carbonyl compounds, smoothly proceeded in the presence of KF/18-crown-6 to give the corresponding methano[60]fullerene derivatives in moderate to good yields.

CHEMOSPECIFICITY IN ARYLATIONS OF δ- AND γ-KETOCARBOXYLIC ACIDS WITH P2O5–MsOH, TfOH, AND RELATED ACIDIC MEDIA

ABSTRACT Remarkable contrast between chemospecificities in acid-mediated arylation of δ- and γ-ketocarboxylic acids was revealed: in the presence of P2O5–MsOH, TfOH, PPA, and MsOH, arylation of δ-ketocarboxylic acid 1A with arenes takes place at the carboxycarbonyl carbon, while that of γ-ketocarboxylic acid 1B takes place at the ketone carbonyl carbon, specifically.

Unexpected switch in regioselectivity of tether-directed Bingel-type biscyclopropanations depending on the leaving groups at tethered active methylene moieties

The regioselectivity of tether-directed Bingel-type biscyclopropanations of [60]fullerene was switched depending on the leaving groups at tethered active methylene moieties; the reactions of [60]fullerene with unhalogenated tethered bis(active methylene) derivatives/I2 and with brominated derivatives in the presence of 1,7-diazabicyclo[5.4.0]undec-7-ene gave trans-4-adducts predominantly, while the reactions with chlorinated derivatives afforded equatorial-adducts almost exclusively.