A5002845487- Synthetic Organic Chemistry Methods
- Marine Sponges and Natural Products
- Asymmetric Synthesis and Catalysis
- Microbial Natural Products and Biosynthesis
- Chemical synthesis and alkaloids
- Oxidative Organic Chemistry Reactions
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Carbohydrate Chemistry and Synthesis
- Advanced Synthetic Organic Chemistry
- Traditional and Medicinal Uses of Annonaceae
- Chemical Synthesis and Analysis
- Alkaloids: synthesis and pharmacology
- Marine Toxins and Detection Methods
- Cancer Treatment and Pharmacology
- Synthesis and Catalytic Reactions
- Bioactive Natural Diterpenoids Research
- Bioactive Compounds and Antitumor Agents
- Synthesis and Biological Activity
- Axial and Atropisomeric Chirality Synthesis
- Crystallography and molecular interactions
- Synthesis of Organic Compounds
- Chemical Synthesis and Reactions
- Cyclopropane Reaction Mechanisms
- Phytochemical compounds biological activities
Waseda University
2016-2025
Advanced Engineering (Czechia)
2019
Tokyo University of Science
2000-2007
Hokkaido University
1994-2004
The University of Tokyo
2000-2001
Scripps Research Institute
1997-2000
Nagoya University
1994-1999
University of California, San Diego
1997-1998
A highly regio- and diastereoselective TiCl4-mediated vinylogous Mukaiyama aldol reaction using the chiral vinylketene silyl N,O-acetal has been developed. The present provides a unique effective means of controlling remote asymmetric induction. methyl group at alpha-position is important in achieving high level stereoselectivity. From synthetic point view, this methodology can provide one-step construction delta-hydroxy-alpha,gamma-dimethyl-alpha,beta-unsaturated carbonyl unit that seen...
An efficient and convenient method for one step conversion of trimethylsilylacetylenes into haloacetylenes has been developed. This is sufficiently mild to apply a variety substrates having many kinds functional group. The validity this demonstrated in the synthesis simple model compound esperamicin/calicheamicin aglycon.
[reaction: see text] The first enantioselective total synthesis of convolutamydines B and E has been achieved using our vinylogous Mukaiyama aldol reaction. features highly diastereoselective reaction with isatin instead aldehydes to construct a chiral center convolutamydines. Additionally, the absolute configuration natural convolutamydine determined as R by its CD spectrum.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTotal Synthesis of (-)-Grayanotoxin IIIToshiyuki Kan, Seijiro Hosokawa, Shinji Nara, Masato Oikawa, Shinya Ito, Fuyuhiko Matsuda, and Haruhisa ShirahamaCite this: J. Org. Chem. 1994, 59, 19, 5532–5534Publication Date (Print):September 1, 1994Publication History Published online1 May 2002Published inissue 1 September 1994https://pubs.acs.org/doi/10.1021/jo00098a009https://doi.org/10.1021/jo00098a009research-articleACS PublicationsRequest reuse...
Taxol-like activity is exhibited by eleutherobin (1), one of the most promising antitumor agents isolated from nature in recent years. The first total synthesis this compound also provided a route to two biologically active analogues, thus enabling structure–activity relationships within family be established.
C-Glycosidation is of great significance in the organic synthesis optically active materials, since it allows introduction carbon chains to sugar chirons and use nuclei as a chiral pool well source. Silylacetylenes are sufficiently reactive form ‘sugar acetylenes’ for selective various acetylenic groups an alpha-axial manner at anomeric position D-hexopyranose rings. 1,4-Anti induction, on other hand, gives different stereochemical outcome case C-glycosidation pentopyranose glycals. The...
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSynthesis of the Tricyclic Core Eleutherobin and Sarcodictyins Total Synthesis Sarcodictyin AK. C. Nicolaou, J.-Y. Xu, S. Kim, T. Ohshima, Hosokawa, J. PfefferkornView Author Information Department Chemistry The Skaggs Institute for Chemical Biology, Scripps Research 10550 North Torrey Pines Road La Jolla, California 92037 Biochemistry University San Diego 9500 Gilman Drive, 92093 Cite this: Am. Chem. Soc. 1997, 119, 46,...
A synthesis of the C14-C35 segment macrolide ring model poecillastrin C has been achieved. The C14-C23 was synthesized by stereoselective Mukaiyama aldol reaction between ketene silyl N,O-acetal possessing chiral oxazolidinone auxiliary and O-acetyl lactol prepared conjugate addition followed iodolactonization. C24-C35 constructed three vinylogous reactions. Both segments were coupled diisobutylaluminium hydride (DIBALH) reduction to produce moiety macrocyclic model.
The total synthesis of the cytotoxic marine natural products eleutherobin (1) and eleuthosides A (2) B (3) is described. strategy involves glycosidation (+)-carvone-derived intermediate 7 with arabinose-derived trichloroacetimidate 9 followed by base-induced ring closure elaboration to afford dihydroxy eneynone 19. Selective hydrogenation 19 led generation intramolecular collapse dienone 20 furnishing 21 thence 22 required structural framework target molecules. Finally, esterification mixed...
The total synthesis of cytotoxic marine natural products possessing tubulin polymerization and microtubule stabilization properties, sarcodictyins A (7) B (8), is described. Two related approaches to these target molecules have been developed, both utilizing (+)-carvone (9) as starting material. first approach involves a stereoselective construction acetylenic aldehyde 27 (Scheme 2) while the second proceeds through more direct but less selective sequence similar intermediate 36 3). Both...
Three compounds related to the AB fragments of ciguatoxin and gambiertoxin 4b two diastereomers (at C-2 position) ABC fragment have been synthesized in enantiomeric form. The stereochemistry position was introduced selectively from corresponding pentose derivative. Construction A ring with its side chain completed by Nicholas type cyclization an acetylene bis(cobalthexacarbonyl) complex followed reductive decomplexation.
A new class of potential antitumor agents with a taxol-like mechanism action is presented by the sarcodictyins 1. Modification reported syntheses permitted preparation additional derivatives, biological properties which are highly dependent upon structure.
A convergent total synthesis of khafrefungin was accomplished on the basis (1) highly stereoselective TiCl4-mediated vinylogous Mukaiyama aldol reaction using vinylketene silyl N,O-acetal and (2) syn-selective enal 5a ethyl ketone 6 followed by anti-dehydration under Mitsunobu conditions.
Asymmetric vinylogous aldol reaction is a powerful methodology to introduce multi functional group in the stereoselective manner. Recently, we have developed highly Mukaiyama reactions using vinylketene N,O-acetals possessing chiral oxazolidone. Our has been applied asymmetric syntheses of natural products establish short and efficient routes. This review focuses on total products. Keywords: Vinylogous reaction, N, O-acetal, remote stereoinduction, synthesis, product, polyketide
The Kobayashi aldol reaction is one of the most powerful methods to synthesize polyketide skeleton and has been applied total synthesis natural products. This methodology used construct anti-aldol products, only a few precedents on syn-selective are known. A by using E,E-vinylketene silyl N,O-acetal an excess amount Lewis acid presented.
The Kobayashi aldol reaction has been used to construct anti-aldol products by remote stereoinduction. Since the product of a typical polyketide structure, this applied total synthesis natural products. By varying reaction, it was found that with acetals in presence Lewis acid proceeded give syn adducts high stereoselectivity. This is first example stereoselective chiral dienol ether and acetals.
ConspectusThe construction of libraries acyclic polyketides remains a challenging topic, mostly due to the difficulties associated with finding right balance between diversity and brevity for synthetic routes leading polyketides. Recently, relatively short methods have been developed applied synthesis natural products. However, these often suffer from limited respect arrangement functional groups stereochemistry, as usually require reactions that direct multiple simultaneously in one step....
Chemokine (C-C motif) receptor 8 (CCR8), the chemokine for ligand 1 (CCL1), is expressed in T-helper type-2 lymphocytes and peritoneal macrophages (PMφ) involved various pathological conditions, including adhesions. However, role of CCR8 inflammatory responses not fully elucidated. To investigate function macrophages, we compared cytokine secretion from mouse PMφ or bone marrow-derived (BMMφ) stimulated with Toll-like (TLR) ligands deficient (CCR8-/-) wild-type (WT) mice. We found that...