A5065936845- Crystallization and Solubility Studies
- Advanced Synthetic Organic Chemistry
- Chemical synthesis and alkaloids
- X-ray Diffraction in Crystallography
- Carbohydrate Chemistry and Synthesis
- Chemical Synthesis and Analysis
- Synthetic Organic Chemistry Methods
- Glycosylation and Glycoproteins Research
- Asymmetric Synthesis and Catalysis
- Phytochemicals and Medicinal Plants
- Alkaloids: synthesis and pharmacology
- Asymmetric Hydrogenation and Catalysis
- Microbial Natural Products and Biosynthesis
- Lysosomal Storage Disorders Research
- Sulfur-Based Synthesis Techniques
- Fluorine in Organic Chemistry
- Biochemical and Molecular Research
- Biological Activity of Diterpenoids and Biflavonoids
- Radical Photochemical Reactions
- Synthesis of Indole Derivatives
- Bioactive Compounds and Antitumor Agents
- Photochromic and Fluorescence Chemistry
- Enzyme Catalysis and Immobilization
- Immune Cell Function and Interaction
- Phytochemical Studies and Bioactivities
Kyushu University
2020-2024
Keio University
2013-2023
University of California, Berkeley
2019-2023
University of Colorado Boulder
2023
Hunan University of Science and Engineering
2023
Shihezi University
2023
Yancheng Teachers University
2023
Soochow University
2023
Charles Darwin University
2023
Jiangxi Normal University
2023
Abstract A chemoselective approach for the total synthesis of (±)‐gephyrotoxin has been developed. The key to success was utilization N ‐methoxyamides, which enabled direct coupling amide with an aldehyde and selective reductive nucleophilic addition in presence a variety sensitive electrophilic functional groups, such as methyl ester. This minimized use protecting‐group manipulations redox reactions, resulted most concise efficient described date.
A unified total synthesis of stemoamide-type alkaloids is reported. Our synthetic approach features the chemoselective convergent assembly five-membered building blocks via stemoamide as common precursor to tetracyclic natural products. The consists two successive coupling reactions three blocks. first reaction vinylogous Michael addition/reduction sequence, which enables gram-scale stemoamide. second a nucleophilic addition While lactone-selective affords saxorumamide and isosaxorumamide,...
C-Glycoside analogs of naturally occurring glycoconjugates are useful tools for chemical biology studies, but their synthesis usually requires protection the hydroxyl groups glycosyl donors. Here we report protecting-group-free and photoredox-catalyzed C-glycosylation with sulfinates Michael acceptors via Giese radical addition.
The acetal (O-glycoside) bonds of glycans and glycoconjugates are chemically biologically vulnerable, therefore C-glycosides interest as more stable analogs. We hypothesized that, if the O-glycoside linkage plays a vital role in glycan function, biological activities C-glycoside analogs would vary depending on their substituents. Based this idea, we adopted "linkage-editing strategy" for creation (pseudo-glycans). designed three types pseudo-glycans with CH2 CHF linkages, which resemble...
C-Glycosides are metabolically stable mimics of natural O-glycosides and expected to be useful tools for investigation the biological functions glycans. Here, we describe synthesis a series aryl vinyl C-glycosides by stereoinvertive sp3–sp2 cross-coupling reactions 2-deoxyglycosyl boronic acid derivatives with or halide, mediated photoredox/nickel dual catalytic system. Hydrogenation afforded C-linked 2′-deoxydisaccharide analogues.
Abstract The development of a two‐step synthesis multi‐substituted N ‐methoxyamines from ‐methoxyamides is reported. Utilization the ‐methoxy group as reactivity control element was key to success in this synthesis. first reaction involves ‐methoxyamide/aldehyde coupling reaction. Whereas ordinary amides cannot condense with aldehydes intermolecularly due poor nucleophilicity amide nitrogen, enhances enabling direct second process nucleophilic addition ‐methoxyamides. Incorporation into...
We describe a new synthetic approach for C-linked glycolipid analogues, in which the cleavable O-glycosidic linkage is replaced by carbon unit. Direct C-glycosylation of conformationally constrained and stable C1-sp3 hybridized xanthate carbohydrate with carefully designed sphingosine units afforded CH2-linked analogue antitumor-active KRN7000 its glucose congener.
The collective synthesis of pentacyclic stemoamide-type alkaloids is recognized as a daunting task despite high demand for comprehensive biological profiling these natural products. In this Letter, we report unified seven and two unnatural derivatives. keys to success are (1) the chemoselective assembly four five-membered building blocks, (2) direct oxidation pyrrolidine products pyrrole derivatives, (3) stereodivergent construction totally E- or Z-substituted butenolides.
This article describes the full details of our total syntheses gephyrotoxin and perhydrogephyrotoxin. Our central strategy toward synthesis is based on use an N-methoxy group as...
Abstract A chemoselective approach for the total synthesis of (±)‐gephyrotoxin has been developed. The key to success was utilization N ‐methoxyamides, which enabled direct coupling amide with an aldehyde and selective reductive nucleophilic addition in presence a variety sensitive electrophilic functional groups, such as methyl ester. This minimized use protecting‐group manipulations redox reactions, resulted most concise efficient described date.
Abstract Our research group has been exploring a lactam strategy for the concise total synthesis of complex alkaloids. In this article, we report full details unified stemoamide-type alkaloids by chemoselective assembly five-membered rings based on strategy. First, and gram-scale tricyclic stemoamide was achieved vinylogous Michael addition-reduction sequence an unsaturated γ-lactam with γ-lactone, followed N-alkylation to form seven-membered ring. From as common intermediate, nucleophilic...
We report the iridium-catalyzed, stereoselective conversion of secondary alcohols or ketones to anti-1,3-diols by silylation C-H bonds γ oxygen and oxidation resulting oxasilolane. The in silyl ethers derived from is enabled a catalyst formed simple bisamidine ligand. occurs with high selectivity at bond over distal primary proximal bonds. Initial mechanistic investigations suggest that source newly achieved reactivity long lifetime binding constant strongly electron-donating
Glycoconjugate analogues in which the sp3 -hybridized C2 position of carbohydrate structure (normally bearing a hydroxy group) is converted into compact sp2 exomethylene group are expected to have unique biological activities. We established ligand-controlled Tsuji-Trost-type glycosylation methodology directly prepare variety these 2-exomethylene pseudo-glycoconjugates, including glucosylceramide analogues, an α- or β-selective manner. Glucocerebrosidase GBA1 cleaves synthetic...
Molecules containing trifluoromethoxyaryl groups are of interest in pharmaceutical, agrochemical, and materials science research, due to their unique physical electronic properties. Many the known methods synthesize aryl trifluoromethyl ethers require harsh reagents highly controlled reaction conditions rarely occur when heteroaromatic units present. The two-step O-trifluoromethylation phenols via xanthates is one such method that suffers from these drawbacks. Herein, we report a for...
A versatile thermal Overman rearrangement of enantioenriched, cyclic allylic alcohols providing tertiary amines has been developed. The vinyl bromide used to control enantioselectivity in a preceding CBS reduction is utilized as synthetic handle for the preparation α-amino ketones and related derivatives an asymmetric fashion.
Harringtonine (HT), produced from Cephalotaxus species, is known to exhibit potent antiproliferative activity against myeloid leukemia cells by inhibiting protein synthesis. A previous study using acute promyelocytic (HL-60) raised the possibility that C-5′ methyl group of HT plays an important role in regulating cell line activity. In order investigate effect hydrocarbon chains at on resultant activity, was replaced with various straight- and branched-chain hydrocarbons corresponding...
Abstract Totally substituted butenolide including two tetrasubstituted olefins is a distinct structural motif seen in Stemona alkaloids, but efficient methods for its synthesis are not well developed. As an ongoing program aimed at the collective total of stemoamide group, we report stereodivergent method to give either (E)- or (Z)-totally from same intermediate. While AgOTf-mediated elimination via E1-type mechanism results formation kinetic (Z)-tetrasubstituted olefin, subsequent...
Abstract C-Glycoside analogues of native glycans are useful molecular tools for medicinal chemistry and chemical biology due to their resistance cellular glycoside hydrolases. We previously reported an α-selective direct C-glycosylation 2-deoxy-β-glycosyl boronate through a Ni/photoredox-catalyzed stereoinvertive cross-coupling reaction. Here we report complementary stereoretentive synthetic method the preparation β-C-glycosides from similar precursor addition C(sp2) anion followed by...
We designed and synthesized a series of derivatives containing the right-side DFGH-ring structure physalin-type natural products, decorated with hydrophobic substituent. The synthetic scheme utilizes highly efficient, one-pot protocol for simultaneous construction GH-ring system, promoted by HF/pyridine. Among compounds synthesized, 5d inhibited TNF-α-stimulated NF-κB activation similar potency to physalin B.
Abstract C-Aryl glycosides have attracted considerable interest as biologically active natural products and O-aryl glycoside mimetics in drug discovery. Here, we describe a straightforward synthesis of C-aryl by photoredox/Ni dual-catalyzed reductive cross-coupling between glycosyl bromides aryl bromides. This methodology enables highly α-stereoselective glucosides, galactosides, mannosides.
Human orthogonal enzymes (HOEs) do not show the same activities as endogenous of human cells and thus are useful amplification to detect antigen proteins in biological samples.Here, we evaluate a new HOE from Escherichia coli, α-sulfoquinovosidase (α-SQase).We confirmed that activity α-SQase did exist examined cell lines, it was applicable live-cell enzyme-linked immunosorbent assay (ELISA) which membrane protein on detected without inactivating enzymes, pretreatment required for ELISA using...