Publications by authors named "Yasuhiro Yamashita"

77 Publications

Chiral Metal Salts as Ligands for Catalytic Asymmetric Mannich Reactions with Simple Amides.

J Am Chem Soc 2021 Apr 6. Epub 2021 Apr 6.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

Catalytic asymmetric Mannich reactions of imines with weakly acidic simple amides were developed using a chiral potassium hexamethyldisilazide (KHMDS)-bis(oxazoline) potassium salt (K-Box) catalyst system. The desired reactions proceeded to afford the target compounds in high yields with high diastereo- and enantioselectivities. It was suggested that a K enolate interacted with K-Box to form a chiral K enolate that reacted with imines efficiently. In this system, K-Box (potassium salt of Box) worked as a chiral ligand of the active potassium species.
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http://dx.doi.org/10.1021/jacs.0c13317DOI Listing
April 2021

Nitrogen-Doped Carbon Enables Heterogeneous Asymmetric Insertion of Carbenoids into Amines Catalyzed by Rhodium Nanoparticles.

Angew Chem Int Ed Engl 2021 Mar 15. Epub 2021 Mar 15.

The University of Tokyo, Department of Chemistry, School of Science, 7-3-1 Hongo, Bunkyo-ku, 113-0033, Tokyo, JAPAN.

Development of stable heterogeneous catalyst systems is a crucial subject to achieve sustainable society. Though metal nanoparticles are robust species, the study of asymmetric catalysis by them has been restricted because methods to activate metal nanoparticles without causing metal leaching were limited. We developed Rh nanoparticle catalysts (NCI-Rh) supported on nitrogen-doped carbon as a solid ligand to strongly interact with metals for asymmetric insertion of carbenoids into N-H bonds cocatalyzed by chiral phosphoric acid. Nitrogen dopants played a crucial role in both catalytic activity and enantioselectivity while almost no catalysis was observed with Rh nanoparticles immobilized on supports without nitrogen dopants. Various types of chiral a -amino acid derivatives were synthesized in high yields with high enantioselectivities and NCI-Rh could be reused in seven runs. Furthermore, we demonstrated the corresponding continuous-flow reaction using a column packed with NCI-Rh. The desired product was obtained efficiently for over 90 h through the reactivation of NCI-Rh and the chiral source could be recovered.
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http://dx.doi.org/10.1002/anie.202102506DOI Listing
March 2021

Well-Dispersed Trifluoromethanesulfonic Acid-Treated Metal Oxide Nanoparticles Immobilized on Nitrogen-Doped Carbon as Catalysts for Friedel-Crafts Acylation.

Chem Asian J 2021 Feb 29;16(3):232-236. Epub 2020 Dec 29.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, 113-0033, Bunkyo-ku, Tokyo, Japan.

Although strong acid-treated metal oxides are useful heterogeneous superacid catalysts for various organic transformations, they usually have a limited density of acidic sites due to their low surface areas. Herein, heterogeneous trifluoromethanesulfonic acid immobilized nitrogen-doped carbon-incarcerated titanium nanoparticle (NP) catalysts have been developed that are composed of well-dispersed, small Ti NPs (ca 7 nm) that are otherwise difficult to achieve using acid-treated metal oxides. The catalysts showed high activity for Friedel-Crafts acylation with low titanium loading (2 mol%, <1 mg of metal for 1 mmol of substrate). A range of microscopic, spectroscopic and physicochemical studies revealed that the nitrogen-doped carbon immobilized the trifluoromethanesulfonic acid and that the addition of metals further changed the nature of the acidic species and enhanced catalytic activity.
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http://dx.doi.org/10.1002/asia.202001274DOI Listing
February 2021

Hydrogen-Bonding-Assisted Cationic Aqua Palladium(II) Complex Enables Highly Efficient Asymmetric Reactions in Water.

Angew Chem Int Ed Engl 2021 Feb 16;60(7):3407-3411. Epub 2020 Dec 16.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan.

Metal-bound water molecules have recently been recognized as a new facet of soft Lewis acid catalysis. Herein, a chiral palladium aqua complex was constructed that enables carbon-hydrogen bonds of indoles to be functionalized efficiently. We embraced a chiral 2,2'-bipyridine as both ligand and hydrogen-bond donor to configure a robust, yet highly Lewis acidic, chiral aqua complex in water. Whereas the enantioselectivity could not be controlled in organic solvents or under solvent-free conditions, the use of aqueous environments allowed the σ-indolylpalladium intermediates to react efficiently in a highly enantioselective manner. This work thus describes a potentially powerful new approach to the transformation of organometallic intermediates in a highly enantioselective manner under mild reaction conditions.
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http://dx.doi.org/10.1002/anie.202009989DOI Listing
February 2021

Chiral Calcium-Catalyzed Asymmetric Epoxidation Reactions Using Hydrogen Peroxide as the Terminal Oxidant.

Chem Pharm Bull (Tokyo) 2018 ;66(9):847-850

Department of Chemistry, School of Science, The University of Tokyo.

Asymmetric epoxidation reactions of chalcone derivatives catalyzed by chiral calcium complexes using hydrogen peroxide were developed. The epoxidation reactions proceeded smoothly to afford the desired products in good yields with good enantioselectivities. This is the first example of chiral calcium-catalyzed asymmetric epoxidation reactions using hydrogen peroxide as the terminal oxidant.
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http://dx.doi.org/10.1248/cpb.c18-00485DOI Listing
July 2019

Catalytic alkylation reactions of weakly acidic carbonyl and related compounds using alkenes as electrophiles.

Org Biomol Chem 2018 08;16(33):5969-5972

Department of Chemistry, School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan.

Catalytic alkylation reactions of weakly acidic carbonyl and related pronucleophiles such as amides, esters, and sulfonamides with substituted alkenes have been reported. In the presence of a strong Brønsted base catalyst system, potassium hexamethyldisilazide and 18-crown-6 ether, the desired reactions proceeded in high yields at ambient temperature with a wide substrate scope. These are atom-economical catalytic alkylation reactions of carbonyl and related compounds.
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http://dx.doi.org/10.1039/c8ob00941dDOI Listing
August 2018

Catalytic enantioselective aldol reactions.

Chem Soc Rev 2018 Jun;47(12):4388-4480

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan.

Recent developments in catalytic asymmetric aldol reactions have been summarized. Enantioselective aldol reactions are important methods to synthesize β-hydroxy carbonyl compounds in optical pure form, and as such, numerous successful chiral catalysts were designed and applied for asymmetric aldol reactions. This review article is organized under the categories of: (1) catalytic enantioselective aldol reactions of preformed enolates, (2) catalytic enantioselective direct-type aldol reactions using chiral metal catalysts, (3) catalytic enantioselective direct-type aldol reactions using organocatalysts, (4) catalytic enantioselective aldol reactions in aqueous media. Examples of the aldol reactions that employ simple carbonyl compounds will be also the focus of this review.
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http://dx.doi.org/10.1039/c7cs00824dDOI Listing
June 2018

Catalytic Direct-Type Addition Reactions of Alkylarenes with Imines and Alkenes.

Angew Chem Int Ed Engl 2018 06 7;57(23):6896-6900. Epub 2018 May 7.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan.

Catalytic addition reactions of very weakly acidic nonactivated alkylarenes such as toluene and its derivatives were developed by using a strongly basic mixed catalyst system under mild reaction conditions. The addition reactions with imines and alkenes proceeded smoothly under proton-transfer conditions to afford the desired products in good to high yields, and high levels of regio- and stereoselectivity were achieved. It was also revealed that the asymmetric addition reaction of an alkylarene was possible.
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http://dx.doi.org/10.1002/anie.201711291DOI Listing
June 2018

N-terminal-pro-B-type-natriuretic peptide associated with 2-year mortality from both cardiovascular and non-cardiovascular origins in prevalent chronic hemodialysis patients.

Ren Fail 2018 Nov;40(1):127-134

b Department of Hemovascular Medicine and Artificial Organs, Faculty of Medicine , University of Miyazaki , Miyazaki , Japan.

N-terminal-pro-B-type-natriuretic peptide (NT-proBNP) was a predictive marker of cardiovascular disease (CVD)-related death in chronic dialysis patients. NT-proBNP was also correlated with markers of inflammation, malnutrition and protein-energy wasting. We hypothesized whether NT-proBNP was also associated with non-CVD death in chronic dialysis patients. A prospective observational study for incidence of death in chronic dialysis patients was conducted. Prevalent chronic dialysis patients (n = 1310) were enrolled and followed for 24 months. One hundred forty-four deaths were recorded. Area under the curve using ROC analysis for NT-proBNP showed: all causes of death (0.761), CVD-related (0.750), infection and malignancy-related (0.702) and others and unknown (0.745). After adjusting for age, sex, hemodialysis vintage, cardiothoracic ratio, mean pre-dialysis systolic blood pressure, dry weight and basal kidney disease, the hazard ratios (95% confidence intervals) per 1-log NT-proBNP calculated using multivariate Cox analysis were: all causes of death, 3.83 (2.51-5.85); CVD-related, 4.30 (2.12-8.75); infection and malignancy-related, 2.41 (1.17-4.93); and others and unknown origin, 5.63 (2.57-12.37). NT-proBNP was significantly associated not only with CVD-relate but also with non-CVD-related deaths in this population of prevalent chronic dialysis patients.
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http://dx.doi.org/10.1080/0886022X.2018.1437047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6014467PMC
November 2018

Catalytic Carbon-Carbon Bond-Forming Reactions of Weakly Acidic Carbon Pronucleophiles Using Strong Brønsted Bases as Catalysts.

Chemistry 2018 Jan 29;24(1):10-17. Epub 2017 Nov 29.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.

Catalytic carbon-carbon bond-forming reactions of weakly acidic carbon pronucleophiles with N-aryl imines, α,β-unsaturated amides, and others under proton-transfer conditions were developed by designing strongly basic reaction intermediates known as product bases. The reactions proceed smoothly in the presence of a catalytic amount of strong base such as KH or alkaline metal amides. Modification of the metal cations by using chiral macrocyclic crown ethers allowed catalytic asymmetric 1,4-addition reactions to proceed with high enantioselectivities. This concept can be applied to Brønsted-base-catalyzed reactions of a wide range of weakly acidic carbon pronucleophiles.
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http://dx.doi.org/10.1002/chem.201703404DOI Listing
January 2018

Catalytic Stereoselective 1,4-Addition Reactions Using CsF on Alumina as a Solid Base: Continuous-Flow Synthesis of Glutamic Acid Derivatives.

Angew Chem Int Ed Engl 2017 08 25;56(35):10330-10334. Epub 2017 Jul 25.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.

A novel methodology using CsF⋅Al O as a highly efficient, environmentally benign, and reusable solid-base catalyst was developed to synthesize glutamic acid derivatives by stereoselective 1,4-addition of glycine derivatives to α,β-unsaturated esters. CsF⋅Al O showed not only great selectivity toward 1,4-addtion reactions by suppressing the undesired formation of pyrrolidine derivations by [3+2] cycloadditions, but also offered high yields for the 1,4-adduct with excellent anti diastereoselectivities. The catalyst was well characterized by using XRD, F MAS-NMR and F NMR spectroscopy, FT-IR, CO -TPD, and XPS. And highly basic F from Cs AlF was identified as the most probable active basic site for the 1,4-addition reactions. Continuous-flow synthesis of 3-methyl glutamic acid derivative was successfully demonstrated by using this solid-base catalysis.
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http://dx.doi.org/10.1002/anie.201701789DOI Listing
August 2017

Identification of a common single nucleotide polymorphism at the primer binding site of D2S1360 that causes heterozygote peak imbalance when using the Investigator HDplex Kit.

Int J Legal Med 2017 Nov 6;131(6):1531-1535. Epub 2017 Apr 6.

Department of Forensic Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo, Tokyo, 113-8421, Japan.

Phenomena known as null alleles and peak imbalance can occur because of mutations in the primer binding sites used for DNA typing. In these cases, an accurate statistical evaluation of DNA typing is difficult. The estimated likelihood ratio is incorrectly calculated because of the null allele and allele dropout caused by mutation-induced peak imbalance. Although a number of studies have attempted to uncover examples of these phenomena, few reports are available on the human identification kit manufactured by Qiagen. In this study, 196 Japanese individuals who were heterozygous at D2S1360 were genotyped using an Investigator HDplex Kit with optimal amounts of DNA. A peak imbalance was frequently observed at the D2S1360 locus. We performed a sequencing analysis of the area surrounding the D2S1360 repeat motif to identify the cause for peak imbalance. A point mutation (G>A transition) 136 nucleotides upstream from the D2S1360 repeat motif was discovered in a number of samples. The allele frequency of the mutation was 0.0566 in the Japanese population. Therefore, human identification or kinship testing using the Investigator HDplex Kit requires caution because of the higher frequency of single nucleotide polymorphisms at the primer binding site of D2S1360 locus in the Japanese population.
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http://dx.doi.org/10.1007/s00414-017-1571-0DOI Listing
November 2017

Catalytic Direct-type 1,4-Addition Reactions of Alkylazaarenes.

Angew Chem Int Ed Engl 2017 04 20;56(16):4520-4524. Epub 2017 Mar 20.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan.

1,4-addition reactions of alkylazaarenes catalyzed by strong Brønsted bases have been developed for the first time. The desired reactions with α,β-unsaturated amides proceeded under mild reaction conditions to give the 1,4-adducts in high yields. Both ortho- and para-substituted azaarenes afforded the desired adducts in high yields. Regioselective reactions of di- or trimethylpyridine were found to be possible depending on the acidity of the α-hydrogen atoms. Furthermore, a candidate of allosteric protein kinase modulators was synthesized in two steps. An asymmetric variant of this reaction was also found to be feasible.
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http://dx.doi.org/10.1002/anie.201611374DOI Listing
April 2017

Development of chiral metal amides as highly reactive catalysts for asymmetric [3 + 2] cycloadditions.

Beilstein J Org Chem 2016 13;12:1447-52. Epub 2016 Jul 13.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan.

Highly efficient catalytic asymmetric [3 + 2] cycloadditions using a chiral copper amide are reported. Compared with the chiral CuOTf/Et3N system, the CuHMDS system showed higher reactivity, and the desired reactions proceeded in high yields and high selectivities with catalyst loadings as low as 0.01 mol %.
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http://dx.doi.org/10.3762/bjoc.12.140DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4979734PMC
August 2016

Development of a Simple Adjustable Zinc Acid/Base Hybrid Catalyst for C-C and C-O Bond-Forming and C-C Bond-Cleavage Reactions.

Chem Asian J 2016 Sep 25;11(17):2372-6. Epub 2016 Aug 25.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.

A newly designed zinc Lewis acid/base hybrid catalyst was developed. By adjusting the Lewis acidity of the zinc center, aldol-type additions of 2-picolylamine Schiff base to aldehydes proceeded smoothly to afford syn-aldol adduct equivalents, trans-N,O-acetal adducts, in high yields with high selectivities. NMR experiments, including microchanneled cell for synthesis monitoring (MICCS) NMR analysis, revealed that anti-aldol adducts were formed at the initial stage of the reactions under kinetic control, but the final products were the trans-(syn)-N,O-acetal adducts that were produced through a retro-aldol process under thermodynamic control. In the whole reaction process, the zinc catalyst played three important roles: i) promotion of the aldol process (C-C bond formation), ii) cyclization process to the N,O-acetal product (C-O bond formation), and iii) retro-aldol process from the anti-aldol adduct to the syn-aldol adduct (C-C bond cleavage and C-C bond formation).
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http://dx.doi.org/10.1002/asia.201600682DOI Listing
September 2016

Apoprotein B/Apoprotein A-1 Ratio and Mortality among Prevalent Dialysis Patients.

Clin J Am Soc Nephrol 2016 05 15;11(5):840-6. Epub 2016 Feb 15.

Division of Circulatory and Body Fluid Regulation, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan.

Background And Objectives: In dialysis patients, the associations between apoprotein profile and all-cause or cardiovascular disease (CVD)-related mortality are not well known. We, therefore, investigated whether apoprotein levels are associated with these events.

Design, Setting, Participants, & Measurements: We undertook a prospective observational cohort study of prevalent hemodialysis patients aged ≥18 years (n=1081), who were followed for 4 years (2011-2014). Outcomes were all-cause and CVD-related mortality. Predictors used were baseline apoprotein levels, particularly the apoprotein B (apo B)/ apoprotein A-1 (apo A-1) ratio. A Cox regression analysis was used to calculate the hazard ratios (HRs) for mortality. Apo A-1, apo B, and apo B/ apo A-1 ratio were analyzed with adjustments in three models: model 1, basic adjustment for age and sex; model 2, basic adjustments plus dialysis conditions (dialysis vintage, mean predialysis systolic blood pressure, dry weight, and mean intradialytic weight gain); and model 3, model 2 plus metabolic and inflammatory conditions (basal kidney disease, serum albumin, C-reactive protein level, and statin use).

Results: Of the 1081 patients included in the study, 203 deaths were recorded, 92 of which were related to CVD. The apo B/ apo A-1 ratio was significantly associated with all-cause and CVD-related mortality when analyzed by 1-SD increments or quartile IV versus I in all models. In model 3, HRs and 95% confidence intervals (95% CIs) for 1-SD increments of apo B/ apo A-1 ratio for all-cause mortality or CVD-related mortality were: HR, 1.16 (95% CI, 1.00 to 1.35), or HR, 1.38 (95% CI, 1.11 to 1.71), respectively, and for quartile IV versus I: HR, 1.65 (95% CI, 1.05 to 2.57), or HR, 2.56 (95% CI, 1.21 to 5.40), respectively. Apo A-1 was significantly associated with both mortalities in models 1 and 2. However, apo B was only significantly associated with CVD-related mortality in model 3.

Conclusions: Apoprotein measurement, especially the apo B/ apo A-1 ratio, was significantly associated with all-cause and CVD-related mortality in prevalent dialysis patients.
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http://dx.doi.org/10.2215/CJN.09830915DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4858486PMC
May 2016

Zinc Amide Catalyzed Regioselective Allenylation and Propargylation of Ketones with Allenyl Boronate.

Org Lett 2015 Dec 1;17(24):6042-5. Epub 2015 Dec 1.

Department of Chemistry, School of Science, The University of Tokyo , Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

Zinc amide catalyzed, regioselective allenylation and propargylation of ketones with allenyl boronate is reported. Tertiary allenyl and homopropargyl alcohols were obtained, respectively, in high selectivities, from the same starting materials, simply by changing the reaction conditions. The substrate scope was wide. Mechanistic studies suggest that the reactions are controlled under kinetic and thermodynamic conditions.
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http://dx.doi.org/10.1021/acs.orglett.5b03045DOI Listing
December 2015

Highly Efficient Electrohydrodynamic Pumping: Molecular Isomer Effect of Dielectric Liquids, and Surface States of Electrodes.

ACS Appl Mater Interfaces 2015 Nov 2;7(44):24492-500. Epub 2015 Nov 2.

Department of Materials Science and Engineering, National Defense Academy , Yokosuka 239-8686, Japan.

Highly efficient electrohydrodynamic (EHD) pumping was obtained by a combination of a dielectric liquid having a molecular isomer and electrodes with a smooth surface. Four kinds of surface states of Cu electrodes were processed by conventional mechanical polishing, fine diamond paste polishing, chemical etching and Au vapor deposition. A series of hydrofluoroether liquids (HFEs) were used as dielectric liquids: C3F7OCH3 (HFE-7000), C4F9OCH3 (HFE-7100), C4F9OC2H5 (HFE-7200), C6F13OCH3 (HFE-7300), and C5H5F6OC3HF6 (HFE-7600). The coexistence of normal (n-) and isomer (i-) HFEs and their molar fractions were examined by NMR spectroscopy. Among the dielectric liquids, the hybrid n- and i-HFE-7600 showed highly efficient EHD pumping, where the electric current, I, was sufficiently suppressed by the smooth surface of the electrodes. The maximum hydrostatic pressure Δpmax was ∼7500 Pa with 12 kV and I = 19 μA. The smooth surface of the electrodes contributes not only to the formation of a stable electric double layer (EDL) but also to the prevention of charge injection from the electrodes. Polarization pumping derived from the stable EDL enables highly efficient energy transfer without discharging, or damage to the sample and electrodes. The dipole moments of the HFEs were estimated by density functional theory calculations. The hydrostatic pressure was found to be proportional to the difference in the calculated dipole moment between n- and i-HFEs. Numerical simulations were carried out to examine the experimentally obtained electrode gap dependence of the hydrostatic pressure.
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http://dx.doi.org/10.1021/acsami.5b05778DOI Listing
November 2015

Catalytic asymmetric endo-selective [3+2] cycloaddition reactions of Schiff bases of α-aminophosphonates with olefins using chiral metal amides.

Chem Commun (Camb) 2015 Dec;51(96):17064-7

Department of Chemistry, School of Science, The University of Tokyo Hongo, Bunkyo-ku, Tokyo, Japan.

Catalytic asymmetric endo-selective [3+2] cycloaddition reactions of Schiff bases of α-aminophosphonates with olefins are described. While the efficient asymmetric synthesis of several phosphonate analogues of proline derivatives is important in bioorganic chemistry, a direct catalytic method to prepare optically active endo [3+2] cycloadducts of α-aminophosphonates with olefins has never been developed. We found for the first time that catalyst systems prepared from Group 11 metal amides with the (R)-FeSulphos ligand were effective for the asymmetric endo-selective [3+2] cycloaddition to afford the desired proline phosphonate analogues in high yields with high endo- and high enantioselectivities.
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http://dx.doi.org/10.1039/c5cc07066jDOI Listing
December 2015

Catalytic Asymmetric 1,4-Addition Reactions of Simple Alkylnitriles.

Chem Asian J 2015 Oct 1;10(10):2143-6. Epub 2015 Jun 1.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan.

The development of catalytic asymmetric carbon-carbon bond-forming reactions of alkylnitriles that do not have an activating group at the α-position, under proton-transfer conditions, is a challenging research topic. Here, we report catalytic asymmetric direct-type 1,4-addition reactions of alkylnitriles with α,β-unsaturated amides by using a catalytic amount of potassium hexamethyldisilazide (KHMDS) with a chiral macro crown ether. The desired reactions proceeded in high yields with good diastereo- and enantioselectivities. To our knowledge, this is the first example of catalytic asymmetric direct-type 1,4-addition reaction of alkylnitriles without any activating group at the α-position.
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http://dx.doi.org/10.1002/asia.201500405DOI Listing
October 2015

Catalytic asymmetric direct-type 1,4-addition reactions of simple amides.

J Am Chem Soc 2015 Apr 26;137(13):4336-9. Epub 2015 Mar 26.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

The development of catalytic asymmetric direct-type reactions of less acidic carbonyl compounds such as amides and esters has been a challenging theme in organic chemistry for decades. Here we describe the asymmetric direct 1,4-addition reactions of simple amides with α,β-unsaturated carbonyl compounds using a catalytic amount of a novel chiral catalyst consisting of a potassium base and a macrocyclic chiral crown ether. The desired 1,5-dicarbonyl compounds were obtained in high yields with excellent diastereo- and enantioselectivities. This is the first example of a highly enantioselective catalytic direct-type reaction of simple amides. In addition, the structure of the chiral potassium catalyst has been investigated by X-ray crystallographic, dynamic (1)H NMR, and MALDI-TOF MS analyses.
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http://dx.doi.org/10.1021/jacs.5b01943DOI Listing
April 2015

Catalytic imine-imine cross-coupling reactions.

Chem Commun (Camb) 2014 Nov;50(86):13041-4

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

We report here efficient catalytic imine-imine cross-coupling reactions based on an umpolung strategy; an imine bearing a 9-fluorenyl moiety on its nitrogen atom, which acted as a nucleophile, reacted with another imine to afford an imine-imine cross-coupling adduct in high yield. Furthermore, a chiral guanidine acted as a chiral catalyst for these coupling reactions, and optically active 1,2-diamines were obtained in high yields with high enantioselectivities.
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http://dx.doi.org/10.1039/c4cc06156jDOI Listing
November 2014

White urine due to urinary tract infection.

Kidney Int 2014 Sep;86(3):655

Faculty of Medicine, Department of Rheumatology, Infectious Diseases and Laboratory Medicine, University of Miyazaki, Miyazaki, Japan.

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http://dx.doi.org/10.1038/ki.2014.23DOI Listing
September 2014

A cooperative water effect in proazaphosphatrane-catalysed heterocycle synthesis.

Chem Commun (Camb) 2014 Mar 14;50(25):3288-91. Epub 2014 Feb 14.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

The synthesis of oxazolines and imidazolines was achieved by activation of isocyanides with water. Mechanistic studies show that the organosuperbase proazaphosphatrane is tolerant of water within the reaction medium, with a beneficial and cooperative effect being observed.
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http://dx.doi.org/10.1039/c3cc49808eDOI Listing
March 2014

Metal amides as the simplest acid/base catalysts for stereoselective carbon-carbon bond-forming reactions.

Chemistry 2013 Jul 17;19(29):9420-7. Epub 2013 Jun 17.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.

In this paper, new possibilities for metal amides are described. Although typical metal amides are recognized as strong stoichiometric bases for deprotonation of inert or less acidic hydrogen atoms, transition-metal amides, namely silver and copper amides, show interesting abilities as one of the simplest acid/base catalysts in stereoselective carbon-carbon bond-forming reactions.
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http://dx.doi.org/10.1002/chem.201300908DOI Listing
July 2013

[Effectiveness of acupuncture and moxibustion therapy for the treatment of refractory interstitial cystitis].

Hinyokika Kiyo 2013 May;59(5):265-9

The Department of Urology, Faculty of Medicine, University of Miyazaki.

The efficacy of acupuncture and moxibustion treatment was examined on eight female patients with refractory interstitial cystitis (IC) who had been treated conservatively with hydrodistension, intravesical instillation of dimethyl sulfoxide, or oral medication. These patients had received hydrodistension on an average of 2.3±1.8 times. Moxa needles were applied to Ciliao in bladder meridian 32 and Xialiao in bladder meridian 34, and electroacupuncture was performed on Zhongliao in bladder meridian 33 at 3 Hz for 20 min once a week. The bladder condition was assessed by the visual analogue scale (VAS) score, the O'Leary-Sant Interstitial Cystitis Symptom Index (ICSI), the Interstitial Cystitis Problem Index (ICPI), and the maximum voided volume (MVV). After 3 months, patients who showed a reduction of >2 in their VAS score, reduction of <30% of ICSI and ICPI, and increase of >100 ml MVV were considered responders. There were three responders, and after repeated therapy to maintain these effects, they no longer required hydrodistension. Two responders had no recurrence for 48 months or more. Acupuncture and moxibustion resulted in improvement in 38% of the patients (3/8) with refractory IC, and repeated therapy maintained the therapeutic effects. This therapy is traditional and relatively noninvasive. Although its precise mechanism of action is unclear, this study suggests that acupuncture and moxibustion treatment may be a complementary and alternative therapeutic option for refractory IC.
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May 2013

Group 11 metal amide-catalyzed asymmetric cycloaddition reactions of azomethine imines with terminal alkynes.

J Am Chem Soc 2012 Dec 4;134(49):20049-52. Epub 2012 Dec 4.

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.

We developed a 1,3-dipolar cycloaddition reaction of azomethine imines with terminal alkynes catalyzed by group 11 metal amides to provide N,N-bicyclic pyrazolidinone derivatives. This reaction afforded the cycloadducts in a unique 5,7-disubstituted manner. Furthermore, we succeeded in applying this catalysis to asymmetric reactions, and the desired heterocycles were produced in high yields with exclusive regioselectivity and high enantioselectivity. Mechanistic studies elucidated a stepwise reaction pathway and critical features that determine the regioselectivity.
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http://dx.doi.org/10.1021/ja311150nDOI Listing
December 2012

Recommendations on bioanalytical method stability implications of co-administered and co-formulated drugs by Global CRO Council for Bioanalysis (GCC).

Bioanalysis 2012 Sep;4(17):2117-26

Advion Bioanalytical Laboratories, Quintiles, NY, USA.

An open letter written by the Global CRO Council for Bioanalysis (GCC) describing the GCC survey results on stability data from co-administered and co-formulated drugs was sent to multiple regulatory authorities on 14 December 2011. This letter and further discussions at different GCC meetings led to subsequent recommendations on this topic of widespread interest within the bioanalytical community over the past 2 years.
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http://dx.doi.org/10.4155/bio.12.192DOI Listing
September 2012

Facile preparation of allylzinc species from allylboronates and zinc amide via a boron-to-zinc exchange process and their reactions with carbonyl compounds, imines and hydrazones.

Chem Commun (Camb) 2012 Oct;48(83):10319-21

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, 113-0033, Tokyo, Japan.

Facile formation of allylzinc species from allylboronate and zinc amide was discovered. The boron-to-zinc exchange process occurred smoothly to afford the corresponding allylzinc amides, which were successfully employed in catalytic allylation reactions with electrophiles. Asymmetric catalysis using a chiral zinc amide is also reported.
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http://dx.doi.org/10.1039/c2cc34340aDOI Listing
October 2012