Small-molecule H-bond donors in asymmetric catalysis.

Asymmetric 1,3-Dipolar Cycloaddition Reactions

Huisgen's 1,3-dipolar cycloadditions become nonconcerted when copper(I) acetylides react with azides and nitrile oxides, providing ready access to 1,4-disubstituted 1,2,3-triazoles and 3,4-disubstituted isoxazoles, respectively. The process is highly reliable and exhibits an unusually wide scope with respect to both components. Computational studies revealed a stepwise mechanism involving unprecedented metallacycle intermediates, which appear to be common for a variety of dipoles.

Copper(I)-catalyzed synthesis of azoles. DFT study predicts unprecedented reactivity and intermediates.

Asymmetric multicomponent reactions involve the preparation of chiral compounds by the reaction of three or more reagents added simultaneously. This kind of addition and reaction has some advantages over classic divergent reaction strategies, such as lower costs, time, and energy, as well as environmentally friendlier aspects. All these advantages, together with the high level of stereoselectivity attained in some of these reactions, will force chemists in industry as in academia to adopt this new strategy of synthesis, or at least to consider it as a viable option. The positive aspects as well as the drawbacks of this strategy are discussed in this Review.

Asymmetric multicomponent reactions (amcrs): the new frontier

140 years ago Adolf von Baeyer proposed the structure of a heteroaromatic compound which revolutionized organic and medical chemistry: indole. After more than a century, indole itself and the complexity of naturally occurring indole derivatives continue to inspire and influence developments in synthetic chemistry. In particular, the ubiquitous presence of indole rings in pharmaceuticals, agrochemicals, and functional materials are testament to the ever increasing interest in the design of mild and efficient synthetic routes to functionalized indole derivatives. This Review emphasizes the achievements in the selective catalytic functionalization of indoles (C-C bond-forming processes) over the last four years.

Catalytic Functionalization of Indoles in a New Dimension

/pdf/x-ray-crystallographic-study-and-thermogravimetric-analysis-3bz5k5ya8u.pdf

X-Ray Crystallographic Study and Thermogravimetric Analysis of Tetrammine-Carbonatocobalt(III) Nitrate Hemihydrate, [Co(NH3)4CO3]NO3.0.5H2O.

/pdf/a-single-crystal-x-ray-structure-determination-of-pb3-s2o3-2-4vmm8oj1co.pdf

A single-crystal X-ray structure determination of Pb3(S2O3)2(CH3COO)2

The synthesis, crystal structure and thermal transformation of a new caesium zinc hydrogen phosphate hydrate, CsZn2.5(HPO4)3·2H2O, is reported. This material crystallised from a gel with molar composition 1 ZnO∶0.48 P2O5∶0.24 Cs2O∶12 H2O∶4.8 MeCO2H, and pH of 1.0, after two months at room temperature. The crystal structure of CsZn2.5(HPO4)3·2H2O has layers built from PO4 and ZnO4 tetrahedra and with other zinc atoms forming octahedra by coordination to water molecules. The zinc octahedra are placed across pseudo 12-rings and caesium ions are placed above and below eight-ring openings. Thermal analysis was performed using thermogravimetric (TG) and differential scanning calorimetric (DSC) measurements. Two weight losses were detected and assigned to expulsion of crystal water and water from condensation of hydrogen phosphate. DSC was used to estimate enthalpy changes from three thermal events.

New layered caesium zinc hydrogen phosphate, CsZn2.5(HPO4)3· 2H2O; synthesis, crystal structure and thermal transformation

Obtention de cis- et trans-(amino-2 diphenyl-4,5) ethylenetricarbonitrile-1,1,3. Le rapport cis/trans depend de la nature et de la concentration de l'electrolyte et de la concentration du substrat

/pdf/stereochemistry-of-the-electrochemical-hydrodimerization-dycpm39iq5.pdf

Rita G. Hazell

Papers

X-Ray Crystallographic Study and Thermogravimetric Analysis of Tetrammine-Carbonatocobalt(III) Nitrate Hemihydrate, [Co(NH3)4CO3]NO3.0.5H2O.

A single-crystal X-ray structure determination of Pb3(S2O3)2(CH3COO)2

New layered caesium zinc hydrogen phosphate, CsZn2.5(HPO4)3· 2H2O; synthesis, crystal structure and thermal transformation

Stereochemistry of the Electrochemical Hydrodimerization Reaction of Benzylidenemalononitrile. Dependence on Different Parameters.

The First Catalytic Highly Enantioselective Alkylation of Ketimines — A Novel Approach to Optically Active Quaternary α‐Amino Acids.