A5071672563- Asymmetric Synthesis and Catalysis
- Synthetic Organic Chemistry Methods
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Synthesis and Catalytic Reactions
- Catalytic C–H Functionalization Methods
- Chemical Synthesis and Analysis
- Coordination Chemistry and Organometallics
- Catalytic Cross-Coupling Reactions
- Asymmetric Hydrogenation and Catalysis
- Organic Chemistry Cycloaddition Reactions
- Oxidative Organic Chemistry Reactions
- Cyclopropane Reaction Mechanisms
- Chemical Synthesis and Reactions
- Multicomponent Synthesis of Heterocycles
- Chemical Reaction Mechanisms
- N-Heterocyclic Carbenes in Organic and Inorganic Chemistry
- Photosynthetic Processes and Mechanisms
- Radical Photochemical Reactions
- Organic and Inorganic Chemical Reactions
- Light effects on plants
- Axial and Atropisomeric Chirality Synthesis
- Chemical synthesis and alkaloids
- Analytical Chemistry and Chromatography
- Sulfur-Based Synthesis Techniques
Kanazawa University
2015-2024
Tokyo University of Science
2016
Material Sciences (United States)
2004-2015
Mie University
1988-1993
The University of Tokyo
1984-1988
Cyanobacteriochromes (CBCRs) are cyanobacterial members of the phytochrome superfamily photosensors. Like phytochromes, CBCRs convert between two photostates by photoisomerization a covalently bound linear tetrapyrrole (bilin) chromophore. Although phytochromes red/far-red sensors, exhibit diverse photocycles spanning visible spectrum and near-UV (330–680 nm). Two CBCR subfamilies detect to blue light (330–450 nm) via “two-Cys photocycle” that couples bilin 15Z/15E with formation or...
A nickel-catalyzed cross-electrophile coupling reaction between benzyl alcohols and aryl halides has been developed using a homolytic C–O bond cleavage protocol that recently established. The treatment of alcohol halide with nickel catalyst low-valent titanium reagent generated from TiCl4(lutidine) (lutidine = 2,6-lutidine) manganese powder afforded the cross-coupled product in high yield. mechanistic study indicated intermediacy radicals originate alcohols.
Low-valent Ti-mediated homolytic C-O bond cleavage offers unified access to carbon radicals from ubiquitous non-activated tertiary, secondary, and even primary alcohols. In contrast the representative Ti reagents, which were ineffective for this purpose, "TiCl2 (cat)"/Zn (cat=catecholate) was found be specifically active. This method applied addition reactions of alkenes exhibited high generality yields. More than 50 combinations examined. The excellent cost-efficiency accessibility further...
A catalyst-free [5 + 1] cycloaddition reaction between isocyanides and C,N-cyclic N'-acyl azomethine imines as the "isocyanophile" leading to novel heterocycles has been developed. These reactions proceeded quickly cleanly afford corresponding imin-1,3,4-oxadiazin-6-one derivatives in high excellent yields. wide range of were applicable this reaction.
A concise method to directly generate benzyl radicals from alcohol derivatives has been developed. The simple and inexpensive combination of TiCl4(collidine) (collidine = 2,4,6-collidine) manganese powder afforded a low-valent titanium reagent, which facilitated homolytic cleavage benzylic C–OH bonds. application radical conjugate addition reactions demonstrated the broad scope this method. reaction various with electron-deficient alkenes furnished corresponding adducts.
Certain cyanobacteria alter their photosynthetic light absorption between green and red, a phenomenon called complementary chromatic acclimation. The acclimation is regulated by cyanobacteriochrome-class photosensor that reversibly photoconverts green-absorbing (Pg) red-absorbing (Pr) states. Here, we elucidated the structural basis of green/red photocycle. In Pg state, bilin chromophore adopted extended C15- Z , anti structure within hydrophobic pocket. Upon photoconversion to Pr isomerized...
Abstract The catalytic asymmetric 1,3-dipolar cycloaddition of nitrile oxides to an achiral allyl alcohol was achieved by the use a amount diisopropyl (R,R)-tartrate as chiral auxiliary afford corresponding (R)-2-isoxazolines with high enantioselectivity. In order realize reproducible higher stereoselection, addition small ethereal compound such 1,4-dioxane crucial.
A new method for the highly effective synthesis of α-siloxyamides is described. The addition isocyanide to aldehyde proceeded smoothly in presence silanol give corresponding high yields. wide range aldehydes and isocyanides are applicable this reaction.
Abstract The asymmetric 1,3-dipolar cycloaddition of a nitrile oxide to an achiral allyl alcohol was achieved by the use (R,R)-diisopropyl tartrate as chiral auxiliary. Treatment with diethylzinc and tartrate, followed addition hydroximoyl chloride, afforded corresponding (R)-2-isoxazolines excellent enantioselectivity.
Abstract The first regio- and enantioselective hetero Diels–Alder reaction of nitroso compound with dienol has been realized utilizing tartaric acid ester as a chiral auxiliary the corresponding cycloadduct was obtained in complete regioselectivity excellent enantioselectivity up to 92% ee.
Abstract The Simmons-Smith reaction starting from allylic alcohols using (R,R)-diethyl tartrate as a chiral auxiliary was found to proceed enantioselectively; i.e., the treatment of with diethylzinc and diethyl tartrate, followed by diiodomethane, afforded corresponding cyclopropylmethyl in optically active form.
Abstract Reduction of β-hydroxy ketone O-benzyl oximes with lithium aluminum hydride in the presence sodium or potassium methoxide afforded corresponding syn-β-amino alcohols highly stereoselective manner. A lythraceae alkaloid, lasubine II, was synthesized stereoselectively by applying this method.
Abstract The asymmetric 1,3-dipolar cycloaddition of azomethine imines to allyl alcohol was achieved by utilizing diisopropyl (R,R)-tartrate as a chiral auxiliary afford the corresponding optically active trans-pyrazolidines with excellent regio-, diastereo-, and enantioselectivities.
Abstract Optically active silicon substituted cyclopropylmethyl alcohols were synthesized through asymmetric Simmons-Smith reaction; that is, the reaction of γ-silicon allylic with diethylzinc and diiodomethane utilizing (+)-diethyl tartrate as a chiral auxiliary was found to afford corresponding high stereoselectivity up 92% ee.
Abstract It was observed that diastereofacial selectivity in the addition reaction of organometallics to chiral imines derived from (R)-2-methoxy-1-phenylethylamine regulated under appropriate conditions; i. e., organolithium and organocerium reagents added re-face selectively, while organocopper attacked si-face. The utility present method demonstrated enantioselective synthesis solenopsin A.
Abstract The asymmetric addition of alkynylzinc reagents, prepared in situ from dialkylzinc and 1-alkynes, to nitrones was achieved by utilizing di(t-butyl) (R,R)-tartrate as a chiral auxiliary afford the corresponding optically active (R)-α-substituted propargylic N-hydroxylamines. By product-like N-hydroxylamine, unprecedented enhancement enantioselectivity observed N-hydroxylamines up 95% ee.
Abstract The asymmetric 1,3-dipolar cycloaddition of azomethine imines to homoallylic alcohols was achieved by utilizing diisopropyl (R,R)-tartrate as a chiral auxiliary give the corresponding optically active trans-pyrazolidines with excellent regio-, diastereo-, and enantioselectivities. catalytic use also effective in presence MgBr2.
Abstract Cyclization of N-(propargylic)hydroxylamines catalyzed by AgBF4 afforded the corresponding 4-isoxazolines in good yields. Copper salts were found to promote further transformation acylaziridines. The combined use and CuCl realized direct into cis-acylaziridines.
A multicomponent reaction of isocyanides and C,N-cyclic N′-acyl azomethine imines in the presence TMSCl NaN3 leads to tetrazole derivatives. These reactions proceeded cleanly afford corresponding 1,5-disubstituted tetrazoles containing a tetrahydroisoquinoline skeleton high excellent yields.
Desymmetrization of the divinyl carbinol 1,4-pentadien-3-ol was accomplished by asymmetric 1,3-dipolar cycloaddition azomethine imines based on a magnesium-mediated, multinucleating chiral reaction system utilizing diisopropyl (R,R)-tartrate as auxiliary. The corresponding optically active trans-pyrazolidines, each with three contiguous stereogenic centers, were obtained excellent regio-, diastereo-, and enantioselectivity, results high 99% ee. This shown to be applicable both aryl-...
Abstract A one‐pot O ‐phosphinative Passerini/Pudovik reaction has been developed, based on reacting aldehydes, isocyanides, and phosphinic acids followed by the addition of second aldehydes to form corresponding α‐(phosphinyloxy)amide derivatives. This is first reported instance a Passerini‐type, isocyanide‐based multicomponent using acid instead carboxylic acid. The nucleophilicity phosphinate group allows subsequent catalytic Pudovik‐type reaction, affording highly functionalized...