Susumu Saito 교수

Proper design of acid-base catalysis has been shown to be effective for achieving high reactivity and selectivity in the asymmetric direct aldol reaction during the development of diamine-Brønsted acid types of catalyst. In this study, two principal approaches have been implemented to create a new type of catalysis and high catalytic efficiency: one is the creation of a highly viable acidic function within acid-base catalysts; the other is the creation of rather complicated but more cooperativel

As electronic devices and integrated circuits get smaller and smaller, eventually quantum-mechanic effects take over. As Saito discusses in his Perspective, results reported by Collins et al. in the same issue demonstrate the use of carbon nanotubes to create nanometer-scale devices known as diodes. Rather than fighting the effects of quantum mechanics, such devices make excellent use of quantum effects on the nanometer scale.

Ironing it out: The straightforward N-alkylation using alcohols and iron/amino acid catalysis is described (see scheme). The reaction does not proceed by the conventional “borrowing hydrogen” mechanism, but appears to involve a substitution pathway (SN) at the sp3 carbon atom bearing the hydroxy group of the alcohol. Developing a catalyst that is effective at a near neutral pH was key to the successful N-alkylation. Detailed facts of importance to specialist readers are published as ”Supporting

A novel catalyst system based on complexes of calcium which promote the catalytic asymmetric 1,4-addition reactions and [3+2] cycloaddition reactions of α-amino acid derivatives with α,β-unsaturated carbonyl compounds have been developed. The reactions proceeded smoothly in the presence of 5−10 mol % of the chiral calcium catalyst to afford the desired adducts in high yields with high diastereo- and enantioselectivities. A wide range of α,β-unsaturated esters and amides were applicable, and othe

Barium phenoxide-catalyzed, highly anti-selective direct-type aldol reactions of amides with aldehydes have been developed. In the presence of a slight excess amount of an amide, the desired reactions proceeded smoothly under mild conditions, and a wide range of aromatic, heterocyclic, alpha,beta-unsaturated aldehydes were applicable to afford the desired adducts in high yields with high anti-selectivities. A catalytic, enantioselective reaction of an amide with an aldehyde using a chiral ligand

Mit Wasser geht's besser! Das gilt für direkte Aldolreaktionen wie die gezeigte. Bisher erachtete man Aldehyde mit hoher Wasseraffinität oder Wasserlöslichkeit als für die asymmetrische Synthese nicht zugänglich. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2001/2004/z52724_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any

A cross-coupling reaction of different alcohols was achieved using a pincer-type NHC/PdBr complex as the catalyst precursor, and the reaction, under either Ar or H(2) gas, displayed a broad substrate scope with respect to both primary and secondary alcohol components, with high alcohol product selectivity.

Sterically hindered aluminium aryloxides have been developed as designer Lewis acid catalysts for stereo-, regio- and chemo-selective carbon–carbon bond-forming reactions. Compared with classical Lewis acids, these aluminium reagents coordinate strongly with various oxygen-containing substrates, and this coordination is affected by the steric environment of their ligands. The carbonyl groups of the bound substrates are either electronically activated or sterically deactivated depending on the al

Four different protonic acids and 15 diamines were screened in the catalytic asymmetric direct aldol reaction of three different aldehydes in acetone.

Tetrakis(dimethylamido)diboron and tetrahydroxydiboron are herein reported as new catalysts for the synthesis of aryl amides by catalytic condensation of aromatic carboxylic acids with amines. The developed protocol is both simple and highly efficient over a broad range of substrates. This method thus represents an attractive approach for the use of diboron catalysts in the synthesis of amides without having to resort to stoichiometric or additional dehydrating agents.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTConceptually New Directed Aldol Condensation Using Aluminum Tris(2,6-diphenylphenoxide)Susumu Saito, Masahito Shiozawa, Masahiro Ito, and Hisashi YamamotoView Author Information Graduate School of Engineering, Nagoya University CREST, Japan Science and Technology Corporation (JST) Furo-cho, Chikusa, Nagoya 464-01, Japan Cite this: J. Am. Chem. Soc. 1998, 120, 4, 813–814Publication Date (Web):January 16, 1998Publication History Received7 August 19

We have found the bunching of the lowest three unoccupied states and the pentagon pairing in extractable fullerenes. These should be related to each other since lower unoccupied states are found to be spatially distributed on pentagons. In addition, the presence of both prevalent and rare structural units constituting extractable fullerenes has been revealed. A series of these findings sheds new light on the fullerene growth mechanism and on the design of larger-fullerene conductors.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTAsymmetric Coupling of Phenols with ArylleadsSusumu Saito, Taichi Kano, Hiroo Muto, Masakazu Nakadai, and Hisashi YamamotoView Author Information Graduate School of Engineering, Nagoya University CREST, Japan Science and Technology Corporation (JST) Chikusa, Nagoya 464-8603, Japan Cite this: J. Am. Chem. Soc. 1999, 121, 38, 8943–8944Publication Date (Web):September 10, 1999Publication History Received1 March 1999Published online10 September 1999P