The University of Tokyo · 공학
이시타니 히로우로 교수의 연구실은 주로 촉매를 이용한 고비선택적 유기합성 반응에 중점을 두고 있습니다. 특히 아연, 티타늄, 지르코늄 기반의 새로운 수화물 촉매를 개발하여 안티선택적 알돌 반응, 맨히우 반응, 스테커 반응 등에서 높은 대칭분열 선택성을 확보했습니다. 이는 천연물 합성 및 의약화학 분야에서 중요한 전구체를 효율적으로 제조하는 데 기여합니다. 특히 수소시아니드(HCN)를 직접 사용하는 촉매적 비대칭 스테커 반응은 기존 방법에 비해 간편하고 친환경적인 접근입니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTCatalytic Enantioselective Mannich-Type Reactions Using a Novel Chiral Zirconium CatalystHaruro Ishitani, Masaharu Ueno, and Shū KobayashiView Author Information Department of Applied Chemistry, Faculty of Science Science University of Tokyo (SUT) CREST, Japan Science and Technology Corporation (JST) Kagurazaka, Shinjuku-ku, Tokyo 162, Japan Cite this: J. Am. Chem. Soc. 1997, 119, 30, 7153–7154Publication Date (Web):July 30, 1997Publication Histo
Catalytic enantioselective Mannich-type reactions of silyl enol ethers with aldimines have been successfully performed using a novel chiral zirconium catalyst prepared from zirconium(IV) tert-butoxide (Zr(OtBu)4), 2 equiv of (R)-6,6‘-dibromo-1,1‘-bi-2-naphthol ((R)-6,6‘-Br2BINOL), and N-methylimidazole. The use of aldimines having N-substituted hydroxyphenyl moieties is essential for obtaining high selectivities, and the N-substituted groups were converted to free amines using oxidative cleavage
Catalytic enantioselective Strecker-type reactions of aldimines with tributyltin cyanide (Bu3SnCN) proceeded smoothly in the presence of a novel chiral zirconium catalyst. High levels of enantioselectivities in the synthesis of α-amino nitrile derivatives with wide substrate generality were obtained via these reactions. In addition, hydrogen cyanide (HCN) was successfully used instead of Bu3SnCN as the cyanide source. Catalytic asymmetric Strecker amino acid synthesis starting from achiral aldeh
Strecker reactions of aldimines with Bu<sub>3</sub> SnCN in the presence of the novel chiral zirconium binuclear catalyst 1 provide α-aminonitriles in good yields and with high enantioselectivities. The reaction can be applied to a wide range of substrates. Since both enantiomers of the chiral sources are readily avaibable, both enantiomers of the α-aminonitriles are easily prepared according to this method. L=N-methylimidazole.
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTHighly anti-Selective Catalytic Asymmetric Aldol ReactionsHaruro Ishitani, Yasuhiro Yamashita, Haruka Shimizu, and Shū KobayashiView Author Information Graduate School of Pharmaceutical Sciences The University of Tokyo, CREST Japan Science and Technology Corporation (JST) Hongo, Bunkyo-ku, Tokyo 113-0033 Japan Cite this: J. Am. Chem. Soc. 2000, 122, 22, 5403–5404Publication Date (Web):May 20, 2000Publication History Received13 December 1999Publis
ADVERTISEMENT RETURN TO ISSUECommunicationNEXTA New Reaction of Imines with Alkynyl Sulfides Affording α,β-Unsaturated ThioimidatesHaruro Ishitani, Satoshi Nagayama, and Shū KobayashiView Author Information Department of Applied Chemistry, Faculty of Science, Science University of Tokyo (SUT), Kagurazaka, Shinjuku-ku, Tokyo 162, Japan Cite this: J. Org. Chem. 1996, 61, 6, 1902–1903Publication Date (Web):March 22, 1996Publication History Received31 October 1995Published online22 March 1996Publish
Durch Strecker-Reaktionen von Aldiminen mit Bu3SnCN in Gegenwart des neuartigen chiralen Zr-Katalysators 1 wurden hochenantioselektiv und in guten Ausbeuten α-Aminonitrile erhalten. Hinsichtlich der Substrate ist die Reaktion allgemein anwendbar. Da beide Enantiomere der chiralen Liganden leicht erhältlich sind, lassen sich auch beide Enantiomere der α-Aminonitrile nach dieser Methode einfach herstellen. L = N-Methylimidazol.
Synthesis of β-nitrostyrene derivatives and their following reactions through two-step continuous-flow protocols with heterogeneous catalysts are described. In the first step to provide β-nitrostyrenes from aromatic aldehydes and nitromethane, readily available amino-functionalized silica gel was employed as a catalyst and gave the products continuously for at least 100 h with high selectivity. In the second step, reactions of β-nitrostyrenes, solid bases, immobilized bases, solid acids, and chi
A chiral composite material, derived from the deposition of a chiral nickel-diamine complex via wet impregnation to MCM-41, was shown to be an efficient heterogeneous catalyst for asymmetric 1,4-addition reactions of 1,3-dicarbonyl compounds with nitroalkenes, and of nitromethane with alkylidenemalonates. It was discovered that MCM-41 enhanced the reactivity and improved the stability of the chiral nickel complex that resides within the mesoporous material.
