Search Results 1-20 of 50

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  • π-Allyl Donicity Switch in Catalytic Asymmetric Allylation: Usability of a Robust and Feasible Allyl Methyl Ether

    Suzuki Yusuke , Iwase Shoutaro , Hashimoto Kazuki , Tanaka Shinji , Kitamura Masato

    … <p>A chiral CpRu(II)/<i>p</i>-TsOH combined catalyst is described for asymmetric allylation that reverses the π-allyl donicity of AllX (All: allyl, X: leaving group) from "AllOAc > …

    Chemistry Letters 46(9), 1308-1310, 2017

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  • Total Synthesis of Daphenylline  [in Japanese]

    Yamada Ryosuke , Adachi Yohei , Yokoshima Satoshi , Fukuyama Tohru

    <p>1. 背景</p><p> ダフェニリン(1)は、ユズリハ属植物であるDaphniphyllum loungerasemosumの果実より単離されたダフニフィラムアルカロイドの一種である<sup>1</sup>。このアルカロイド群には、抗HIV</p><p>活性やマウス腫瘍細胞に対する細胞毒性などの生物活性を有 …

    Symposium on the Chemistry of Natural Products, symposium papers 57(0), Oral3, 2015

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  • Inverse electron demand asymmetric cycloadditions of cyclic carbonyl ylides catalyzed by chiral Lewis acids-Scope and limitations of diazo and olefinic substrates

    Suga Hiroyuki , Higuchi Satoshi , Ohtsuka Motoo , Ishimoto Daisuke , Arikawa Tadashi , Hashimoto Yuta , Misawa Shunta , Tsuchida Teruko , Kakehi Akikazu , Baba Toshihide

    … High enantioselectivities (94–96% ee) were obtained for the inverse electron-demand 1,3-dipolar cycloadditions between cyclohexyl vinyl ether and 2-benzopyrylium-4-olate generated via Rh₂(OAc)₄-catalyzed decomposition of o-methoxycarbonyl-α-diazoacetophenone. … The reactions with the other electron-rich dipolarophiles such as allyl alcohol, 2,3-dihydrofuran, and butyl-tert-butyldimethylsilylketene acetal showed moderate enanantioselectivities (60–73% ee). …

    Tetrahedron 66(16), 3070-3089, 2010-04-17

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  • 39 Total Synthesis of Huperzine A(Oral Presentation)  [in Japanese]

    Koshiba Takahiro , Yokoshima Satoshi , Fukuyama Tohru

    … Upon treatment with TBSOTf in the presence of base, 4 underwent unexpected cyclization to give silyl enol ether with bicyclo[3.3.1] skeleton, which was desilylated to provide ketone 13. … The resulting carboxylic acid 15 was converted to methyl carbamate 17 via Curtius rearrangement. … Since Wittig reaction is known to give the wrong stereochemistry, ketone 26 was converted into allyl chloride 28 via a two-step procedure including addition of vinyllithium and treatment with SOCl_2. …

    Symposium on the Chemistry of Natural Products, symposium papers 50(0), 257-262, 2008

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  • Generation and Properties of a Cyclopentadienyl Cation Annelated with Homoadamantene Frameworks

    Kitagawa Toshikazu , Ogawa Kohei , Komatsu Koichi

    強固なシクロアルケン骨格の縮合は、環状π共役系カチオン種を安定化する方法として有効である。本研究では、2個のホモアダマンテン骨格が縮環したシクロペンタジエニル (Cp) カチオンの発生と反応について検討するために、前駆体として新たに合成した塩化物の i) メタノリシス、および ii) ジクロロメタン中でのAg+またはB(C6F5)3による塩化物イオンの引き抜き、を行なった。その結果、i)の条件では …

    Abstracts of Symposium on Physical Organic Chemistry 55(0), 24-24, 2005

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  • Structure and Thermal Behavior of Dissolved Water in Saturated and Unsaturated Esters Studied by FT-IR Spectroscopy.  [in Japanese]

    TAKAOKA Kyo , KOBAYASHI Koichi , TAKAHASHI Masashi , SONE Mototaka

    FT-IRスペクトル法により,8種の含水エステル[酢酸ブチル(BAc),酔酸t-ブチル(TBAc),ヘキサン酸エチル(EH),酢酸ヘキシル(HAc),酢酸2-ヘキセニル(2HEAc),10-ウンデセン酸メチル(MU),リノール酸メチル(ML)およびフタル酸ジオクチル(DOP)]中の溶存水を形成するクラスターの状態を検討した。また,これらのクラスターの熱安定性を調べた.<BR>エステルと …

    NIPPON KAGAKU KAISHI 1999(12), 797-803, 1999

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  • Recent Advancement of Photo-functional Network Polymers  [in Japanese]

    NISHIKUBO Tadatomi , IYO Masami

    以前は, 光機能性ポリマーと言えば感光性樹脂を意味するものであったが, 最近は様々な光機能性高分子が創製され, 次世代の機能性材料として注目されている。本稿では, 多くの光機能性モノマーやポリマーの中で, 光架橋や光硬化反応が関与する興味ある材料の合成や特徴について紹介する。多層回路基板の作成のために耐熱性に優れた感光性樹脂の開発が期待されているが, 最近, 側鎖にエポキシ残基やビニルエーテル残基 …

    Journal of Network Polymer,Japan 18(1), 8-20, 1997

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  • 116(P56) TOTAL SYNTHESIS OF PRESWINHOLIDE A  [in Japanese]

    Nagasawa Kazuo , Nakata Tadashi , Shimizu Isao

    … The aldehyde 3, the C11-C23 segment, was stereoselectively synthesized by an iterative construction of the 1,3-polyol chain using a series of sequential reactions which involved the Sharpless asymmetric epoxidation (Sharpless AE) of allyl alcohol and Pd-catalyzed hydrogenolysis of alkenyl oxirane with HCO_2H as the key reactions. … After conversion of the chiral auxiliary of 23 into the methyl group, 23 was converted into the lactone 29. …

    Symposium on the Chemistry of Natural Products, symposium papers 38(0), 691-696, 1996

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  • 23 Total Synthetic Studies on an Antibiotic, Calbistrin  [in Japanese]

    TATSUTA Kuniaki , HIRAMA Ryusuke , ITOH Manabu , ARAKI Nobuyuki , KITAGAWA Masayuki

    … The tetrahydronaphthalene moiety 8 was synthesized by intramolecular Diels-Alder reaction of silyl dienol ether 7 prepared from methyl α-D-mannopyranoside in 23 steps as shown in Scheme 2. … The anti (20) and syn isomers of the rasemic side chain, tetraene carboxylic acid dimethyl ester, were synthesized from allyl alcohol 15, which was prepared by the aldol reaction of trans-2-methyl-2-butenal and methyl propionate (Scheme 4). …

    Symposium on the Chemistry of Natural Products, symposium papers 38(0), 133-138, 1996

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  • 35 Studies toward the Total Synthesis of Taxusin  [in Japanese]

    Hara R. , Horiguchi Y. , Kuwajima I.

    … The tricyclic skeleton of taxusin 14 was constructed by means of the TMSOTf-mediated intramolecular eight-membered ring cyclization reaction of 13 between the dienol silyl ether and the acetal. … Chemo- and stereoselective functional group transformations of 14 gave allyl alcohol 17, setting up the stage for investigation of the 19β-methyl group installation. … Thus, we succeeded in introduction of the 19β-methyl group on the ring system in high yield. …

    Symposium on the Chemistry of Natural Products, symposium papers 36(0), 266-273, 1994

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  • Synthesis of 5,6,7,8-Tetrahydroquinolines by Thermolysis of Oxime O-Allyl Ethers in the Presence of Boron Trifluoride Etherate

    KOYAMA Junko , OGURA Tamaki , TAGAHARA Kiyoshi , MIYASHITA Masaaki , IRIE Hiroshi

    … Thermolysis of cyclohexanone oxime O-crotyl and O-cinnamyl ether in the presence of BF_3-etherate regioselectively gave 4-methyl- and 4-phenyl-5,6,7,8-tetrahydroquinoline, while the addition of organic bases such as triethylamine and pyridine inhibited the rearrangement. … These findings suggested that the addition of the acid made [1,2] shift the predominant one of the two possible transformations, [1,2] and [2,3] shift, of the O-allyl ethers. …

    Chemical & pharmaceutical bulletin 41(7), 1297-1298, 1993-07-15

  • Synthesis of 5,6,7,8-Tetrahydroquinolines by Thermolysis of Oxime O-Allyl Ethers in the Presence of Boron Trifluoride Etherate.

    KOYAMA Junko , OGURA Tamaki , TAGAHARA Kiyoshi , MIYASHITA Masaaki , IRIE Hiroshi

    … Thermolysis of cyclohexanone oxime O-crotyl and O-cinnamyl ether in the presence of BF<SUB>3</SUB>-etherate regioselectively gave 4-methyl- and 4-phenyl-5, 6, 7, 8-tetrahydroquinoline, while the addition of organic bases such as triethylamine and pyridine inhibited the rearrangement. … These findings suggested that the addition of the acid made [1, 2] shift the predominant one of the two possible transformations, [1, 2] and [2, 3] shift, of the O-allyl ethers. …

    Chemical and Pharmaceutical Bulletin 41(7), 1297-1298, 1993

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  • 76 ASYMMETRIC REACTION USING CYCLITOL AS CHIRAL AUXILIARIES  [in Japanese]

    Akiyama T. , Okada K. , Ishikawa K. , Nishimoto H. , Kuwata T. , Ozaki S.

    … L-Quebrachitol (1L-(-)-2-O-methyl-chiro-inositol) is a naturally abundant chiral cyclitol obtained from the serum of the rubber tree. … SnCl4 promoted addition of allyl silane or sillyl enol ether to 4 also took place to afford single diastereomer exclusively. …

    Symposium on the Chemistry of Natural Products, symposium papers 35(0), 591-597, 1993

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  • AlCl3-N,N-Dimethylaniline: A Novel Benzyl and Allyl Ether Cleavage Reagent.

    Akiyama Takahiko , Hirofuji Hajimu , Ozaki Shoichiro

    … The system also cleaved allyl as well as methyl ethers. …

    Bulletin of the Chemical Society of Japan 65(7), 1932-1938, 1992

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  • Synthesis of telechelic polysiloxanes with mesogenic side chains and their reaction.  [in Japanese]

    KODAIRA Toshiyuki , SHINAGAWA Kazuhiro

    側鎖にメソゲン基を有するテレケリックポリシロキサン (TLS) の合成を行い, TLSを1成分とするブロック共重合体合成の可能性を検討した. OH基を両末端に有するエンドキャップ剤 (EC) の存在下, 1, 3, 5, 7-テトラメチルシクロテトラシロキサンの開環重合により, テレケリックポリメチルヒドロシロキサン (THS) を合成した. その後, THSによるアリル基を有するメソゲンモノマー …

    KOBUNSHI RONBUNSHU 48(2), 97-103, 1991

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  • One-pot synthesis of tetrahydrofuran derivatives from allylic alcohols and vinyl ethers by means of palladium(II) acetate.

    Fugami Keigo , Oshima Koichiro , Utimoto Kiitiro

    … Reaction of allylic alcohol with vinyl ether in the presence of Pd(OAc)<SUB>2</SUB> … Three components were combined at once to produce 4-(3-butenyl)-2-butoxy-4-methyltetrahydrofuran upon treatment of a mixture of 2-methyl-2-propen-1-ol, butyl vinyl ether, and allyl bromide. …

    Bulletin of the Chemical Society of Japan 62(6), 2050-2054, 1989

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  • Reaction of allyl phenyl ether over various liquid metal catalysts.

    Ozawa Sentaro , Sasaki Yoshiki , Ogino Yoshisada

    Allyl phenyl ether has been reacted over various kinds of liquid metal catalysts (Sn, Ga, In, Tl, Pb, Cd, Bi, Zn) and without catalysts in the temperature range of 320–500 °C. … A good correlation between the methyl group-catalyst metal bond energy and kinetic parameters of the <I>o</I>-AP formation reaction has also supported the radicalic transition state model. …

    Bulletin of the Chemical Society of Japan 60(12), 4279-4284, 1987

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  • Studies on dental caries prevention by traditional medicines. X Antibacterial action of phenolic components from mace against Streptococcus mutans.

    HATTORI MASAO , HADA SUMITRA , WATAHIKI AKIKO , IHARA HITOMI , SHU YUE-ZHONG , KAKIUCHI NOBUKO , MIZUNO TOKUO , NAMBA TSUNEO

    … During this experiment, threo-2-(4-allyl-2, 6-dimethoxyphenoxy)-1-(4-hydroxy-3-methoxyphenyl)propan-1-ol methyl ether (6) and guaiacin (8) were isolated for the first time from mace. …

    Chemical and Pharmaceutical Bulletin 34(9), 3885-3893, 1986

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  • Studies on dental caries prevention by traditional medicines. X. Antibacterial action of phenolic components from mace against Streptococcus mutans

    HATTORI M. , HADA SUMITRA , WATAHIKI AKIKO , IHARA HITOMI , SHU YUE-ZHONG , KAKIUCHI NOBUKO , MIZUNO TOKUO , NAMBA TSUNEO

    … During this experiment, threo-2-(4-allyl-2,6-dimethoxyphenoxy)-1-(4-hydroxy-3-methoxyphenyl)propan-1-ol methyl ether (6) and guaiacin (8) were isolated for the first time from mace. …

    Chem Pharm Bull (Tokyo) 34, 3885-3893, 1986

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