Haruro Ishitani

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 Bu₃ 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.