Toshio Nishikawa

ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTImproved Conditions for Facile Overman Rearrangement1Toshio Nishikawa, Masanori Asai, Norio Ohyabu, and Minoru IsobeView Author Information Laboratory of Organic Chemistry, School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-01, Japan Cite this: J. Org. Chem. 1998, 63, 1, 188–192Publication Date (Web):January 9, 1998Publication History Received28 July 1997Published online9 January 1998Published inissue 1 January 1998https://pubs.acs

An efficient and convenient method for one step conversion of trimethylsilylacetylenes into haloacetylenes has been developed. This method is sufficiently mild to apply a variety of substrates having many kinds of functional group. The validity of this method is demonstrated in the synthesis of simple model compound of esperamicin/calicheamicin aglycon.

The toxic principle of puffer-fish poison, (−)-tetrodotoxin (1), has been recognized as a formidable synthetic target since its structure elucidation in 1964. An efficient total synthesis of 1 via the intermediate 2, which was used previously for the synthesis of 11-deoxytetrodotoxin, is described. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z460293_s.pdf or from the author. Please note: The publisher is not responsible for

A precise measurement method for the temperature coefficient of dielectric resonator material was developed. The error of measurement was decreased from 0.5 ppm/°C to 0.05 ppm/°C compared with the conventional method. This measurement method made techniques for improving stability possible, such as for filters, multiplexer and oscillators.

The total synthesis of alpha-C-mannosyltryptophan (C-Man-Trp), a naturally occurring C-glycosylamino acid, was achieved from a commercially available alpha-methyl-D-mannoside in 10 steps including the following key steps: the C-glycosidation of a mannose derivative with a stannylacetylene, Castro indole synthesis, and Sc(ClO4)3-promoted coupling with L-serine-derived aziridine carboxylate. The glucose- and galactose-analogues of C-Man-Trp were also synthesized in a similar manner. Conformational

A dielectric high-power bandpass filter using "quarter-cut TE/sub 01delta/ image resonators" has been developed. The resonator has a high unloaded Q over 7000 and its construction provides a sufficient thermal diffusion path to the metal housing. The insertion loss and the attenuation level of the eight-pole elliptic function type filter are 0.37 dB and 95 dB, respectively. The physical size of the dielectric filter is 280x135x 65 mm, one third to one fifth the volume of conventional cavity reso

Pick your poison: Salient features of a concise synthetic route for the saxitoxin skeleton are a bromonium-ion-initiated cascade cyclization of readily prepared 1 to give tricyclic intermediate 2 and the transformation of the gem-dibromomethylene group into an enol acetate unit. This new route enabled the preparation of 3, a naturally occurring analogue of saxitoxin. Cbz=benzyloxycarbonyl, Ms=methanesulfonyl, Py=pyridine. Detailed facts of importance to specialist readers are published as ”Suppo

Abstract A model compound containing an indole β-lactam moiety bearing vinylchloride in chartellines was synthesized from the Mannich reaction of isatin imine with ketene silyl acetal, β-lactam formation of the resulting β-amino ester, and copper(I)-mediated coupling with (E)-α-chloro-β-iodostyrene.

A stereocontrolled synthesis of a-C-mannosyltryptophan, a new type of glycosyl amino acid, was achieved by Sc(ClO 4 ) 3 mediated coupling between a-C-mannosylindole and L-serine-derived 2-aziridinecarboxylate as a key step.

Tetrodotoxin, a toxic principle of puffer fish poisoning, is a specific blocker of sodium channel. Despite many synthetic efforts since the structure elucidation in 1964, the only total synthesis of the racemic tetrodotoxin has been reported by Kishi and co-workers. In the course of our studies directed toward the total synthesis to analyze biologically interesting issues associated with tetrodotoxin, we accomplished a highly stereocontrolled synthesis of (-)-5,11-dideoxytetrodotoxin in 1999. Ba

Tetrodotoxin, a toxic principle of puffer fish intoxication, is one of the most famous marine natural products due to its densely functionalized structure and potent toxicity. Despite its small molecular size (MW 319 g mol⁻¹), tetrodotoxin has long been well known as a formidable molecule in natural product synthesis. We have devoted more than twenty years to developing synthetic strategies for this molecule, resulting in the preparation of a variety of analogues of tetrodotoxin for biological e

New derivatives of an intriguing marine natural product are now accessible. The first asymmetric synthesis of the simple tetrodotoxin analogue, 5,11-dideoxytetrodotoxin (3), was achieved. Hydroxylation at position C8 of the key intermediate 1 relied on the neighboring trichloroacetamide group, and stereoselective elaboration of the vinyl group gave alpha-hydroxylactone 2, which was transformed into the title compound through a new guanidylation method.

alpha-C-Mannosyltryptophan (alpha-C-Man-Trp) has been found to be a novel post-translational modification of tryptophan found from some biologically important glycoproteins. In order to analyze the biological functions of alpha-C-Man-Trp, we have developed an efficient synthetic strategy for alpha-C-Man-Trp and its glucose and galactose analogues, starting from alpha-C-glycosidation of the corresponding hexapyranoside derivatives with tinacetylene. According to the synthetic routes, we describe