坂本 昌巳

Allylic arylation of cinnamyloxyphenylboronic acid pinacol esters 3, which have arylboronic acid moiety and allylic ether moiety, using a hydrazone 1d-Pd(OAc)(2) system proceeded and gave the corresponding 1,3-diarylpropene derivatives 4 with a phenolic hydroxyl group via a selective coupling reaction of the pi-allyl intermediate to the boron-substituted position of the leaving group.

Palladium-catalyzed decarboxylative coupling of benzoic acid derivatives with arylboroxins gave biaryls using a catalytic amount of Pd(TFA)(2)-hydrazone Id system with Ag2CO3 at 80 degrees C in good yields. We also found that decarboxylative coupling with aryl(trialkoxy)silanes gave biaryls using a Pd(TFA)(2)-hydrazone 1g system with AgF in good yields. 2014 Elsevier Ltd. All rights reserved.

We report a new catalyst system, a morpholine-Pd(OAc)2 complex, for Suzuki-Miyaura coupling of aryl tosylates or mesylates with arylboronic acids to give biaryl compounds. The morpholine-Pd(OAc)2 catalyst system is proposed to be a precursor of the catalytically active species in the coupling reaction. Aryl chlorides and aryl triflates can also be used in this coupling reaction. Altogether, 22 biaryl compounds were obtained using this catalyst system. We report a new catalyst system, a morpholine-Pd(OAc) 2 complex, for Suzuki-Miyaura coupling of aryl tosylates or mesylates with arylboronic acids to give biaryl compounds. The morpholine-Pd(OAc) 2 catalyst system is proposed to be a precursor of the catalytically active species in the coupling reaction. Copyright © 2014 WILEY-VCH Verlag GmbH &amp Co. KGaA, Weinheim.

Organocatalytic tandem reactions of L-phenylalanine-derived tetramic acid with aldehydes allow a one-pot and high-yielding access to a diverse range of novel chiral diols in enantiomerically pure forms. In addition, a new entry of the diols, featuring their unique structures associated with C-2- and pseudo C-2-symmetric chiral motifs, is reported.

Irradiation of three chromone-2-carboxamides with a chiral auxiliary resulted in diastereoselective formation of a C-2-chiral anti-HH dimer scaffold. Selection of the solvent polarity and decreasing the temperature resulted in asymmetric induction with up to 84% diastereomeric excess (de).

An aluminium complex bearing 2-cyclohexyl-6-phenylphenol afforded (5R)-n-isopulegol from (R)-citronellal via the intermolecular Prins reaction with an exceptionally high diastereoselectivity. Using this reaction, L-menthol was obtained with an excellent diastereoselectivity.

A highly reactive catalytic ring-closing ene reaction is discussed. This reaction is catalyzed via novel optically active aluminum BINOL and TADDOL complexes. The kinetic resolution of the racemic analogs of citronellal was affected by these Al catalysts. The BINOL-Al catalyst afforded 68% ee of a diastereomer of isopulegol and 62% ee of citronellal at 47% conversion. The reaction mechanism proposed assumes that the optically active catalyst possesses a metal center between two parallel aromatic rings. We postulate that the edge of the aromatic rings can recognize the methyl group at the 3-position of citronellal, as the rings are oriented in a pseudoparallel orientation. We utilized the kinetic resolution for the synthesis of L-menthol from citral.

The copper-catalyzed asymmetric propargylic amination of propargylic acetates 1 with amines 2 using BICMAP as a chiral ligand gave the desired products 3 in good yields and with moderate to high enantioselectivities (up to 90% ee). (C) 2013 Elsevier Ltd. All rights reserved.

Dynamic atroposelective resolution of chiral salts derived from oily racemic nicotinamides and enantiopure dibenzoyltartaric acid (DBTA) was achieved by crystallization. The absolute structures of the axial chiral nicotinamides were determined by X-ray structural analysis. The chirality could be controlled by the selection of enantiopure DBTA as a chiral auxiliary. The axial chirality generated by dynamic salt formation was retained for a long period after dissolving the chiral salt in solution even after removal of the chiral acid. The rate of racemization of nicotinamides could be controlled based on the temperature and solvent properties, and that of the salts was prolonged compared to free nicotinamides, as the molecular structure of the pyridinium ion in the salts was different from that of acid-free nicotinamides. © 2013 by the authors.

We developed a palladium-catalyzed Mizoroki-Heck type reaction of olefins with such hypervalent iodine reagents as iodobenzene diacetate in good to high yields using 2 mol% of a heterocyclic hydrazone (1b)-Pd(OAc)(2) system in NMP under air at 90 degrees C.

Optically active materials could be generated by simple solidification of achiral materials without an external chiral source. When achiral cis-3,4-diphenylsuccinimides were solidified in the presence of a catalytic amount of DBU by evaporating the solvent with stirring, optically active trans-3,4-diphenylsuccinimides were obtained quantitatively with high enantiomeric excesses. © 2013 The Royal Society of Chemistry.

The palladium-catalyzed asymmetric allylic alkylation of indoles with 1,3-diphenyl-2-propenyl acetate using P/N-type ligands such as N-aryl indole, C-N bond axially chiral aminophosphine (aS)-I4, gave the desired products 1 in good yields and with moderate to high enantioselectivities (up to 90% ee). (C) 2013 Elsevier Ltd. All rights reserved.

Unsymmetrical 1,3-diarylpropenes were synthesized in good to high yields by the palladium-catalyzed allylic arylation of allylic ethers, such as a cinnamyl phenyl ether, with a variety of arylboronic acids using a hydrazone 1a-Pd(OAc)(2) system in DMAc/H2O. Using this catalyst, eugenol was also synthesized from allyl phenyl ether with (4-hydroxy-3-methoxyphenyl) boronic acid pinacol ester.

Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Chiba University received a grant in aid of Program for Promoting High-Quality University Education in 2008. The adopted program includes three sub-programs, which equipped students with abundant knowledge and deep understanding of advanced technology to dissipate the dissociation between technology and university education. Advanced visual learning tools in the programs established safe and understandable chemical experiment education. The programs were effective in diminishing the dispersion of students' ability and improving students' technique of the advanced chemical analysis as well as the fundamental experiment.

The irradiation of methyl 2- and 3-chromonecarboxylate in the presence of various alkenes afforded cyclobutane type adducts, whose structures were established by X-ray structural analysis. Methyl 2-chromonecarboxylate showed higher photochemical reactivity than methyl 3-chromonecarboxylate, in which endo adducts were yielded as major products. © 2012 Springer Science+Business Media Dordrecht.

The irradiation of methyl 2- and 3-chromonecarboxylate in the presence of various alkenes afforded cyclobutane type adducts, whose structures were established by X-ray structural analysis. Methyl 2-chromonecarboxylate showed higher photochemical reactivity than methyl 3-chromonecarboxylate, in which endo adducts were yielded as major products.

The reaction of vinyl ethers with carboxylic acids using iodine as a catalyst under solvent-free conditions was investigated. The reaction of saturated carboxylic acids with vinyl ethers gave the corresponding esters. Mechanistic studies revealed the production of the adduct of the vinyl ether with the carboxylic acid, which then rearranged to form the ester. At low temperatures, the reaction of 2-(1-hydroxycyclohexyl)acetic acid (1) and butyl vinyl ether yielded a butyl ester. However, at a reaction temperature of 80°C, both the esterification and the elimination of a water molecule occurred, yielding the unsaturated butyl ester butyl 2-cyclohexenylacetate. The reaction of 2-((1S,2S,4R)-2-hydroxy-1,7,7- trimethylbicyclo[2.2.1]heptan-2-yl)acetic acid (12) with butyl vinyl ether at low temperatures resulted in a mixture of four compounds. However, similar to the high-temperature (&gt 60°C) reaction of 1, the esterification was accompanied by the elimination of a water molecule to give the unsaturated butyl ester (E)-butyl 2-((1S,4R)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene)acetate. While a g-hydrogen was abstracted to form the endo-type double bond in the reaction of 1, an α-hydrogen was abstracted to form the exo-type double bond in the reaction of 12. © 2013 by Japan Oil Chemists' Society.

側鎖にメチル基のない4-oxabicyclo[4.4.0]dec-1(2)-ene(１)と、１の側鎖にメチル基を有する4-oxabicyclo[4.4.0]decane(７)のような新規二環性エーテルを合成し、これらの香気特性について検討した。さらに、６員環と７員環または８員環の組み合わせ、さらには、二重結合の有無、また側鎖メチル基の有無などで構造を変化させた１２種類の二環性エーテルを合成し、香気特性と化学構造との関連性について検討した。また、最安定化構造を、分子軌道法から計算して求め、最安定化構造と香気特性の関連性についても検討した。

The reaction of olefins with nitrites using iodine as a catalyst under solvent-free conditions was investigated. The reaction of cycloolefins, such as cyclopentene and cyclohexene, with benzonitrile using iodine as a catalyst produced both amide and heterocyclic compounds. The reaction of chiral (+)-camphene with benzonitrile produced racemic (+/-)-N-isobornylbenzamide (N-((1S,2S,4S)-1,7,7-trimethylbicyclo[2.2.1] hept-2-yl)benzamide). This indicated that skeletal rearrangement of camphene as well as amidation occurred. The optimized conditions were determined to be as follows: temperature, 90 degrees C; molar ratio of nitrile:alcohol:iodine:water, 1:5:0.2:1.0; and reaction time, 18 h. The yield was 87% under these conditions. The reaction of (+)-camphene also proceeded with the other aromatic and aliphatic nitrites to produce racemic isobornylamides. However, except for styrene, complex reactions occurred in the reactions of benzonitrile with other terpenic olefins.

3-hydroxy acids, 3-hydroxy-3,7-dimethyloct-6-enoic acid (1) and 3-hydroxy-2,2,3,7-tetramethyloct-6-enoic acid (2), were prepared from 6-methyl-5-hepten-2-one, and they were subsequently used to prepare (2,6,6-trimethyltetrahydropyran-2-ypacetic acid (3) and 2-methy1-2-(2,6,6-trimethyltetrahydropyran-2-yl)propanoic acid (4), respectively, via cyclization with an acidic catalyst such as boron trifluoride diethyl etherate or iodine. The reaction of carboxylic acids 3 and 4 with alcohols, including methanol, ethanol, and 1-propanol, produced the corresponding methyl, ethyl, and propyl esters, which all contained a tetrahydropyran ring. Reduction of carboxylic acids 3 and 4 afforded the corresponding alcohols. Subsequent reactions of these alcohols with several acyl chlorides produced novel esters. The alcohols also reacted with methyl iodide and sodium hydride to provide novel ethers. A one-pot cyclization esterification of 1 to produce esters containing a tetrahydropyran ring, using iodine as a catalyst, was also investigated.

Chiral dihydrobenzofuran-based diphosphine ligand (BICMAP) 1 was used as a ligand for the rhodium(l)catalyzed asymmetric 1,4-addition of arylboronic acids to cyclic enones up to 99% ee. We also found that the BICMAP-rhodium system was an efficient catalyst for the 1,4-addition of alkenylboronic acids to 2-cyclohexenone in good enantioselectivities. (C) 2012 Elsevier Ltd. All rights reserved.

The reaction of esters with nitriles, using iodine as a catalyst under solvent-free conditions, was investigated. For example, 1-phenylethyl acetate reacted with benzonitrile in the presence of iodine to afford the amide, N-(1-phenylethyl)benzamide. Addition of water was effective in promoting amidation. The most suitable conditions were investigated, and determined as follows: temperature = 80 degrees C, molar ratio of nitrile:alcohol:iodine:water = 1:3:0.2:1.0, and reaction time = 18 h. The amidation reactivity depended on the stability of the cationic intermediate formed from the ester. Only the reaction of 2-phenylpropan-2-yl acetate with benzonitrile gave no amide compound; rather, the cyclic compound, 1,1,3-trimethyl-3-phenyl-2,3-dihydro-1H-indene was obtained in 90% yield. The reaction of (-)-bornyl acetate with benzonitrile produced the racemic amide compound, (+/-)-exo-N-isobornylbenzamide, in 82% yield.

N,N-Diallyl-4-methyl-1-propyl-2-quinolone-3-carboxamide afforded chiral crystals of a P2(1) crystal system by spontaneous crystallization. The molecular chirality in the crystal was retained after the crystals were dissolved in a solvent at a low temperature, and the frozen molecular chirality was effectively transferred to the products by a two-step reaction involving hydrogenation and intermolecular photocycloaddition reactions.

The palladium-catalyzed synthesis of unsymmetrical 1,3-diarylpropenes from allyl esters through a MizorokiHeck-type reaction with aryl iodides followed by allyl cross-coupling with a variety of arylboronic acids was developed; the products are obtained in moderate to good yields by using a hydrazonePd(OAc)2 system.

Palladium-catalyzed Mizoroki-Heck type reaction of olefines with aryl trialkoxysilanes gave the arylation products using a catalytic amount of hydrazone Pd(OAc)(2) system with AgF at 60 degrees C in good yields. (C) 2011 Elsevier Ltd. All rights reserved.

テトラヒドロピラン環を有するカルボン酸(2,6,6-trimethyltetrahydropyran-2-yl)acetic acidおよび2-methyl-(2,6,6-trimethyltetrahydropyran-2-yl)acetic acidから誘導した新規エステル、アルコール、エーテルの香気を検討した。また、分子軌道計算により最安定化構造を求め、香気との関連性についても検討した。

Crystal structures and photochemical reactions of three N,N-diallyl-2-quinolone-3-carboxamides were investigated. One quinolonecarboxamide afforded chiral crystals of a P2(1) crystal system by spontaneous crystallization, and the molecular chirality In the crystal was effectively transferred to cyclobutane in 96% ee by an intramolecular 2 + 2 photocycloaddition reaction in the solid state.

Chiral phosphine-prolineamide 1a was employed as an organocatalyst in direct asymmetric aldol reactions of various aromatic aldehydes with ketones. Cyclohexanone led to the aldol products in up to 98% ee and with good diastereoselectivity using 10 mol % of TFA and 30 mol % of prolineamide 1a in DMF at 0 degrees C. (C) 2011 Elsevier Ltd. All rights reserved.

Acyclic amines 1 were obtained by a nucleophilic aromatic substitution (SNAr) reaction and N-methylation followed by silane reduction. The optical resolution of C(aryl)-N(amine) bond atropisomers of amines 1 is described. We found that chiral acyclic amine la can be resolved by crystallization without any outside chiral source. Finally, we demonstrate the ability of chiral amines 1 as a ligand in a palladium-catalyzed asymmetric allylic alkylation (up to 93 % ee).

Selective synthetic routes to coordination polymers [Cu(bpy)(2)(OTf)(2)](n) (bpy = 4,4'-bipyridine, OTf = trifluoromethanesulfonate) with 2- and 3- dimensionalities of the frameworks were established by properly choosing each different solvent solution system. They show a quite similar local coordination environment around the Cu(II) centers, but these assemble in a different way leading to the 2D and 3D building-up structures. Although the two kinds of porous coordination polymers (PCPs) both have flexible frameworks, the 2D shows more marked flexibility than the 3D, giving rise to different flexibility-associated gas adsorption behaviors. All adsorption isotherms for N(2), CO(2), and Ar on the 3D PCP are of type I, whereas the 2D PCP has stepwise gas adsorption isotherms, also for CH(4) and water, in addition to these gases. The 3D structure, having hydrophilic and hydrophobic pores, shows the size-selective and quadrupole-surface electrical field interaction dependent adsorption. Remarkably, the 2D structure can accommodate greater amounts of gas molecules than that corresponding to the inherent crystallographic void volume through framework structural changes. In alcohol adsorption isotherms, however, the 2D PCP changes its framework structure through the guest accommodation, leading to no stepwise adsorption isotherms. The structural diversity of the 2D PCP stems from the breathing phenomenon and expansion/shrinkage modulation.

The Sonogashira coupling reaction of aryl bromides with a variety of terminal alkynes in DMSO at 125 degrees C gave internal arylated alkynes using low-loaded Pd(acac)(2) with hydrazone as a ligand and CuI as the co-catalyst in good yields.

N-(2-methoxy-1-naphthoyl)pyrrolidine afforded chiral crystals by spontaneous crystallization. The molecular chirality in the crystal was retained after dissolving the crystals in a cooled solvent. Kinetic resolution of racemic amines was performed using the provisional chiral molecular conformation derived from chiral crystals.

Palladium-catalyzed cyanation of aryl bromides with potassium hexacyanoferrate(II) trihydrate, K(4)[Fe(CN)6]center dot 3H(2)O as the cyanide source gave benzonitrile derivatives using a catalytic amount of Pd(OCOCF(3))(2) in DMF at 110 degrees C with phosphine-free pyridyl-hydrazone ligand 2c in good yields.

N-(2-Methoxy-1-naphthoyl)piperidine afforded chiral crystals by spontaneous crystallization, and the molecular chirality of the crystals was retained after dissolving them in a cooled solvent. An asymmetric photocycloaddition reaction with a diene was performed using the provisional chiral molecular conformation derived from these chiral crystals.

The reactions of alcohols with nitriles under solvent-free conditions, using molecular iodine as a catalyst, were investigated. The reaction of 1-phenylethanol with propanenitrile produced the amide N-(1-phenylethyl)propanamide, by dehydration and tautomerization, in 71% yield, under the following conditions: temperature = 90 degrees C, alcohol:iodine molar ratio = 1:0.2, alcohol:nitrile molar ratio = 1:5, and reaction time=5 h. The amidation reactivity depended on the stability of the cationic intermediate formed from the alcohol. The reaction of (-)-borneol with benzonitrile produced a racemic amide in 83% yield.

Many examples of solid-state photoreactions using chiral crystals composed of achiral materials and leading to optically active products have been successfully demonstrated and recognized as absolute asymmetric synthesis. Recently, we have discovered a new methodology for asymmetric synthesis using the molecular chirality in crystal as a source of homochirality in fluid media. The chirality can be effectively transferred to optically active products by asymmetric reactions involving nucleophilic reactions and an intermolecular photochemical reaction, and which had so far not been achieved in solid state reactions.

The irradiation of chromone-2-carboxylic esters resulted in the stereo- and regioselective formation of C(2) chiral anti-HR dimers from the triplet excited state. On the contrary, photolysis in the solid-state gave anti-HT dimers exclusively controlled by molecular arrangement in the crystal

N-Aryl indole-derived C-N bond axially chiral phosphine ligands 2a-c were obtained by DDQ oxidation of N-aryl indoline-derived phosphine oxide followed by silane reduction. Resolution of C-N bond atropisomers was achieved by chiral HPLC. The investigation of the rotation barrier for the C-N bond axial stability of phosphines and the determination of the absolute configuration of 2c are described. Finally, the ability of the chiral ligand 2c was demonstrated in a palladium-catalyzed asymmetric allylic alkylation (up to 99% ee). (C) 2010 Elsevier Ltd. All rights reserved.

X-Ray crystallographic analysis of N-(1-naphthyl)-2(1H)-pyrimidinethione revealed that the space group was tetragonal and chiral P4(3). The rate of racemization due to the C-N bond rotation was considerably influenced by the solvent properties. A nonpolar solvent lowers the Delta G(double dagger) value by about 3.0 kcal mol(-1) relative to the value in a polar or a protic solvent. The crystallization of racemic axially chiral pyrimidinethione at high temperature led to the chiral breaking of symmetry up to 91% e.