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A cross-coupling reaction between enol derivatives and silyl ketene acetals catalyzed by GaBr3 took place to give the corresponding α-alkenyl esters. GaBr3 showed the most effective catalytic ability, whereas other metal salts such as BF3 ⋅OEt2 , AlCl3 , PdCl2 , and lanthanide triflates were not effective. Various types of enol ethers and vinyl carboxylates as enol derivatives are amenable to this coupling. The scope of the reaction with silyl ketene acetals was also broad. We successfully observed an alkylgallium intermediate by using NMR spectroscopy, suggesting a mechanism involving anti-carbogallation among GaBr3 , an enol derivative, and a silyl ketene acetal, followed by syn-β-alkoxy elimination from the alkylgallium. Based on kinetic studies, the turnover-limiting step of the reaction using a vinyl ether and a vinyl carboxylate involved syn-β-alkoxy elimination and anti-carbogallation, respectively. Therefore, the leaving group had a significant effect on the progress of the reaction. Theoretical calculations analysis suggest that the moderate Lewis acidity of gallium would contribute to a flexible conformational change of the alkylgallium intermediate and to the cleavage of the carbon-oxygen bond in the β-alkoxy elimination process, which is the turnover-limiting step in the reaction between a vinyl ether and a silyl ketene acetal.

Gold-catalyzed auto-tandem catalysis has been developed for synthesizing 2-aryl-substituted quinolines. The reaction of an aniline bearing an acetal moiety with an aryl alkyne proceeded via formal [4+2]-cycloaddition, which involved the addition of gold acetylide to an oxonium ion to give amino alkyne intermediate and sequential 6-endo-dig cyclization of amino alkyne intermediate by attacking of nitrogen to alkyne moiety activated by gold catalyst. The cationic gold catalyst promoted two different processes by enhancing the nucleophilicity and electrophilicity of alkyne. This convergent synthetic methodology enabled the synthesis of a variety of 2-aryl-substituted quinolines.

Helical peptide foldamer catalyzed Michael addition reactions of nitroalkane or dialkyl malonate to α,β-unsaturated ketones are reported along with the mechanistic considerations of the enantio-induction. A wide variety of α,β-unsaturated ketones, including β-aryl, β-alkyl enones, and cyclic enones, were found to be catalyzed by the helical peptide to give Michael adducts with high enantioselectivities (up to 99%). On the basis of X-ray crystallographic analysis and depsipeptide study, the amide protons, N(2)–H and N(3)–H, at the N terminus in the α-helical peptide catalyst were crucial for activating Michael donors, while the N-terminal primary amine activated Michael acceptors through the formation of iminium ion intermediates.

Hg(OTf)2-catalyzed aryl–allene cyclization accompanied by formation of a quaternary carbon center has been realized. Deuterium-labeling experiments and computational modeling were used to propose a novel catalytic pathway involving direct H-transfer from the aromatic ring to the vinyl mercury moiety followed by mercury 1,2-migration.

Linear polystyrene-stabilized PdO nanoparticles (PS-PdONPs) exhibited high catalytic activity for fluoride-free Hiyama coupling reaction of aryltrimethoxysilanes with a variety of bromoarenes under air in water. In contrast, no desired coupling product was obtained from the Hiyama coupling reaction using linear polystyrene-stabilized Pd nanoparticles (PS-PdNPs) as a catalyst. The different reactivities of PdONPs and PdNPs will be discussed.

In this study, we report the synthesis of benzene-glycol nucleic acids and studies of their biophysical and biological properties. Using (S)-mandelic acid as the starting material, we prepared phosphoramidite units for the synthesis of benzene-glycol nucleic acids. The benzene-glycol moieties effectively replace the sugar groups ordinarily found in DNA and RNA monomers. Oligonucleotides (ONs) containing these nucleoside analogues formed thermally and thermodynamically stable duplexes with complementary DNA and RNA strands and proved to be more resistant (i.e. less susceptible) to 3′-exonuclease than their “natural” counterparts. Furthermore, we demonstrated that a duplex composed of a modified ON and its complementary strand of RNA very effectively elicits RNase H activity.

A procedure for nucleophilic β-alkenylation of N-alkoxyenamines with alkenyl aluminum reagents under mild conditions is reported.

A gold-catalyzed sequential reaction of O -allyl hydroxamates bearing an alkyne moiety has been developed for the preparation of 3-hydroxyisoxazoles and isoxazole-3-ones. Notably, this domino reaction involving cyclization and rearrangement provided facile access to the desired compounds in a highly atom-economical manner.

Regiodivergent vinylogous aza-Morita–Baylis–Hillman reactions of 3-vinylcyclopent-2-en-1-one 1 were developed in a catalyst-controlled manner. While treatment of 1 with N -tosylarylaldimines 2 in the presence of DABCO gave the α-adducts as the sole regioisomer, that in the presence of DMAP gave the unusual γ-adducts in 87–96% regioselectivity.

A novel reductive Fischer indolization of readily available N-aryl conjugated hydrazones with tert-butyl iodide has been developed. In this reaction, tert-butyl iodide is used as anhydrous HI source, and the generated HI acts as a Bronsted acid and a reducing agent. This operationally simple method allows access to various indole derivatives. Furthermore, the procedure can be applied to the synthesis of biologically active compounds.

C4 and C5 diols and alcohols are important commodity chemicals mainly used as monomers in the production of polyesters, polyurethanes and polyethers. C4 and C5, on the other hand, can be used in the fuel industry for the preparation of additives to boost the gasoline octane number. The present critical review covers those reports describing the obtainment of these diols and alcohols from precursors derived from biomass. Emphasis is made on the description of the catalysts required for these transformations and on common traits referring to the bifunctionality combining hydrogenation activity and acidity and on the mechanistic proposals. The need for finding a suitable replacement for noble metals on the composition of these catalysts has been remarked throughout the review.

The air and water stable title electride is characterized by powder XRD, transport, magnetic, and thermodynamic measurements, PES, and DFT calculations.

A series of V-incorporated e-Keggin polyoxometalate-based open framework materials, (NH4)1.8H10 [Zn3Mo11.9V0.1O40] ·6.5H2O, (NH4)1.8H10 [Zn2.7Mo11.6V0.7O40] ·6.5H2O, (NH4)1.8H7 [Zn2.6Mo11.2V1.2O40] ·6H2O, (NH4)2H14 [Mn2.4Mo12V0.2O40] ·5H2O, (NH4)2.2H12 [Mn2.2Mo11.9V0.7O40] ·5H2O, and (NH4)2.2H9 [Mn2.2Mo11.6V1.0O40] ·5H2O, is hydrothermally synthesized from aqueous mixtures of (NH4)6Mo7O24, NH4VO3, Mo, and ZnCl2 or MnO (autoclave, 448 K, 24 h, 53—71% yield of Zn-containing compounds, 35—43% yield of Mn-containing compounds).

Treatment of homoallylic amines with dimethylzinc as radical initiator and chloroform as carbon source leads to the formation of the corresponding β-chlorolactams via Prins-type cyclization of a carbamoyl chloride intermediate.

Recent developments of crystalline Mo3VOx catalysts (MoVO), a new type of oxidation catalysts for selective oxidations of ethane to ethene and of acrolein to acrylic acid, are reviewed. MoVO are formed by the building unit assembly of polyoxomolybdates under hydrothermal conditions. These catalysts are composed of a network arrangement based on a {Mo6O21}6− pentagonal unit and a {MO6} (M = Mo, V) octahedral unit to form a hexagonal channel and a heptagonal channel. Between these channels, the heptagonal channel acts as a micropore of 0.40 nm in diameter which can adsorb small molecules such as CO2, N2, methane, ethane, etc. The size of the heptagonal channel micropore is reversibly and continuously tunable by redox treatment. Interestingly, the heptagonal channel activates ethane inside and acrolein on the channel located over the external surface. Tuning of the heptagonal channel size significantly modifies the catalytic performance for the selective oxidation of ethane. Strong relationships among crystal structure, microporosity, and catalytic performance were observed here.

N , N ′-(Arylmethylene)bisamides were prepared by an acid-catalyzed reaction of arylaldehydes with cinnamamide or acrylamides. The reaction was carried out in refluxing toluene for a few hours, and simple collection of the precipitate gave the desired products. The bisamides were designed as cytotoxic molecules based on the structure of the potently cytotoxic marine natural product (–)-zampanolide. The activities of the bisamides against two cancer cell lines were evaluated, and several compounds were found to show medium potency with IC 50 values in the lower micromolar level.

The total synthesis of (-)-isoschizogamine was accomplished, featuring the construction of the quaternary carbon center by the modified Johnson-Claisen rearrangement in basic media and the facile assembly of the key tetracyclic quinolone intermediate through a cascade cyclization. The characteristic cyclic aminal was constructed by late-stage C-H functionalization at the position adjacent to the lactam nitrogen using a combination of CrO3 and nBu4 NIO4 and subsequent Bi(OTf)3 -mediated cyclization.

A new class of C2 chiral materials was easily prepared by the photodimerization reaction of (R)-N-phenethyl-2-chromonecarboxamide followed by recrystallization. Reduction of the photodimer gave the corresponding alcohol stereoselectively. Both C2 chiral materials worked effectively as ligands for enantioselective ethylation of arylaldehydes using diethylzinc.

The first total syntheses of multifidosides A–C have been achieved. The synthetic strategy is characterized by catalytic site-selective acylation of unprotected glycoside precursors in the final stage of the synthesis. High functional-group tolerance of the site-selective acylation, promoted by an organocatalyst, enabled the conventionally difficult molecular transformation in a predictable and reliable manner. An advantage of this strategy is to avoid the risks of undesired side reactions during the removal of the protecting groups at the final stage of the total synthesis.

The thermal intermolecular [4+2] cycloadditions of vicinal bis(exo-methylene)cyclooctene with carbon dienophiles efficiently produce the bicyclo[6.4.0] framework. Similar cycloadditions with the one-carbon-homologated cyclononene derivatives result in the formation of the bicyclo[7.4.0] skeleton. Both aza- and oxadieonphiles are suitable for this [4+2] reaction and provide the corresponding hetero-Diels–Alder-type products.

Conversion of ester moieties into 4-bromophenyl groups was effected by means of a four-step protocol: a Grignard reaction of the ester with allylmagnesium halides, a ring-closing metathesis, dibromocyclopropanation, and an electrocyclic reaction of the dibromocyclopropanes.

The vicinal functionalization of N-alkoxyenamines, derived in situ from aldehydes and isoxazolidines, has been achieved with the formation of two new carbon–carbon bonds by utilizing an organo-aluminum reagent and subsequent allylmagnesium bromide or tributyltin cyanide as external carbon-centered nucleophiles. By changing the second carbon nucleophile, various amine derivatives were obtained in good yields.

The direct addition reaction of chloroform to cyclopropenes in presence of triethylborane as initiator gives trichloromethylated cyclopropanes in good yields.

Lactones are converted to methyl alkynes and dimethyl allenes in a two-step procedure utilizing a CCl4/PPh3—MeLi—system.

Irradiation of chromone-carboxamides bearing a chiral auxiliary, e.g. (I), results in diastereoselective formation of a C2-chiral anti-HH dimer scaffold.

The first general β-selective C–H arylation of pyrroles has been developed by using a rhodium catalyst. This C–H arylation reaction, which is retrosynthetically straightforward but results in unusual regioselectivity, could result in de novo syntheses of pyrrole-derived natural products and pharmaceuticals. As such, we have successfully synthesized polycyclic marine pyrrole alkaloids, lamellarins C and I, by using this β-selective arylation of pyrroles with aryl iodides (C–H/C–I coupling) and a new double C–H/C–H coupling as key steps.

Depending on the functionality of the substrates used, either saturated or unsaturated six-membered ring products are obtained selectively.

New addition-cyclization sequence for the synthesis of multisubstituted pyrroles is reported.

A new method has been developed for the umpolung α-heteroarylation of ketones via an N-alkoxyenamine. The treatment of ketones with tris(heteroaryl)aluminum reagents in the presence of isoxazolidine gave the corresponding α-heteroarylated ketones in moderate to good yields.

The C-C bond formation proceeds with a range of nucleophiles and leads to an oxidative functionalization of the benzylic C-H bond in tetrahydroisoquinolines and tetrahydro-β-carboline derivatives.

Polycrystalline layered Y2C with quasi-2D anionic electrons confined in the interlayer is prepared by melting stoichiometric amounts of Y shots and C granules under Ar.

Pd-catalyzed amination of iodoarenes with aminopyridine (I) followed by intramolecular C-H arylation in the presence of DBU as base and 2-(dicyclohexylphosphino)biphenyl as catalyst offers a practical synthetic route to α-carbolines.

Single phase V4O9 is prepared by reduction of V2O5 with sulfur using 92—94% of the stoichiometrically required sulfur amount (≈0.23 equiv.

The oxidative homocouplings of lithium enolates of (4S)-3-(3-arylpropanoyl)-4-isopropyl-2-oxazolidinones and (4R, 5S)-1-(3-arylpropanoyl)-3,4-dimethyl-5-phenyl-2-imidazolidinones gave the corresponding R,R-dimers stereoselectively with TiCl(4), PhI(OAc)(2), or CuCl(2) as an oxidant. The stereoselectivity can be explained by a radical coupling mechanism. Optically active dibenzylbutyrolactone lignans, such as (-)-hinokinin and (-)-dimethylmatairesinol, and dibenzylbutanediol lignans, such as (-)-dihydrocubebin and (-)-dimethylsecoisolariciresinol, were synthesized from the major R,R-dimers. The oxidative coupling of (4R, 5S)-1-(3-arylpropanoyl)-3,4-dimethyl-5-phenyl-2-imidazolidinones with LDA-I(2) gave R,S-dimers mainly, and this result can be explained by an S(N)2 mechanism.

A straightforward synthetic method for the construction of benzofuro[2,3-b]pyrrol-2-ones by a novel domino reaction through a radical addition/[3,3]-sigmatropic rearrangement/cyclization/lactamization cascade has been developed. The domino reaction of O-phenyl-conjugated oxime ether with an alkyl radical allows the construction of two heterocycles with three stereogenic centers as a result of the formation of two C-C bonds, a C-O bond, and a C-N bond in a single operation, leading to pyrrolidine-fused dihydrobenzofurans, which are not easily accessible by existing synthetic methods. Furthermore, asymmetric synthesis of benzofuro[2,3-b]pyrrol-2-one derivatives through a diastereoselective radical addition reaction to a chiral oxime ether was also developed.

The total syntheses of the monoterpene indole alkaloids leuconoxine (IX), leuconodine B (VIII) and melodinine E (X) are described.

The application of conjugated oxime ethers to the synthesis of complex chemical scaffolds using domino radical reactions has been described in detail. The triethylborane-mediated hydroxysulfenylation reaction allows for the regioselective construction of a carbon-sulfur bond and a carbon-oxygen bond in a single operation for the formation of β-hydroxy sulfides. This reaction proceeds via a radical pathway involving regioselective thiyl addition and the subsequent trapping of the resulting α-imino radical with O₂, where the imino group enhances the stability of the intermediate radical. Hydroxyalkylation reactions that occur via a carbon radical addition reaction followed by the hydroxylation of the resulting N-borylenamine with O₂ have also been developed. We investigated sequential radical addition aldol-type reactions in detail to explore the novel domino reactions that occur via the generation of N-borylenamine. The radical reaction of a conjugated oxime ether with triethylborane in the presence of an aldehyde affords γ-butyrolactone via sequential processes including ethyl radical addition, the generation of N-borylenamine, an aldol-type reaction with an aldehyde, and a lactonization reaction. A novel domino reaction has also been developed involving the [3,3]-sigmatropic rearrangement of N-boryl-N-phenoxyenamine. The triethylborane-mediated domino reactions of O-phenyl-conjugated oxime ethers afforded the corresponding benzofuro[2,3-b]pyrrol-2-ones via a radical addition/[3,3]-sigmatropic rearrangement/cyclization/lactamization cascade.

The new compounds (IV) and (VII) are characterized by powder XRD, FTIR, and Raman spectroscopy.

Compounds (I) and (II) are evaluated for anti-tumor and anti-inflammatory activity.They show cytotoxicity against HCT116 cells (IC50 6.04 and 47 μM, respectively) and a dose dependent antiinflammatory effect in LPS/IFN-γ-stimulated inflammatory RAW 264.7 macrophage cells.

The VV-substituted polyoxotungstate isomers 1- and 4-[S2VW17O62]5- are prepared as Bu4N+ salts from a Na2WO4-H2SO4/NH4 VO3-NaOH reaction mixture in aqueous MeCN.