Dinitrohydrazines and Interaction of Them with Some Group-II Metals - DFT Treatment

Dinitrohydrazines and interaction of them with some group-II metals have been considered within the restrictions of density functional theory and the basis set applied (B3LYP/6-311++G(d,p)). Dinitrohydrazine has two isomers as geminal and vicinal. The calculations reveal that both of them are structurally stable. The vicinal form electronically is more stable and thermo chemically more favorable than the other isomer. The beryllium magnesium and calcium (1:1) composites of them are considered. The results indicate that only the beryllium composites (geminal and vicinal) are structurally intact while the others undergo decomposition due to reductive cleavage by the metals. The decompositions occurred exhibit variations from one composite to the other.

Synthesis of a Hexameric Magnesium 4-pyridyl Complex with Cyclohexane-like Ring Structure via Reductive C-N Activation

The reaction of [{(Arnacnac)Mg}2] (Arnacnac = HC{MeC(NAr)}2, Ar = 2,6-diisopropylphenyl, Dip, or 2,6-diethylphenyl, Dep) with 4-dimethylaminopyridine (DMAP) at elevated temperatures afforded the hexameric magnesium 4-pyridyl complex [{(Arnacnac)Mg(4-C5H4N)}6] via reductive cleavage of the DMAP C-N bond. The title compound contains a large s-block organometallic cyclohexane-like ring structure comprising tetrahedral (Arnacnac)Mg nodes and linked by linear 4-pyridyl bridging ligands, and the structure is compared with other ring systems. [(Dipnacnac)Mg(DMAP)(NMe2)] was structurally characterised as a by-product.

Facile Access to Triazole-Fused 3,1-Benzoxazines Enabled by Metal-Free Base-Promoted Intramolecular C–O Coupling

A convenient approach to assemble 1,2,3-triazole-fused 4H-3,1-benzoxazines has been developed. Diverse alcohol-tethered 5-iodotriazoles, readily accessible by a modified protocol of Cu-catalyzed (3+2)-cycloaddition, were utilized as precursors of the target fused heterocycles. The intramolecular C–O coupling proceeded efficiently under base-mediated transition-metal-free conditions, furnishing cyclization products in yields up to 96%. Suppression of the competing reductive cleavage of the C–I bond was achieved by the use of Na2CO3 in acetonitrile at 100 °C. This practical and cost-effective procedure features a broad substrate scope and valuable functional group tolerance.

Electro-mediated PhotoRedox Catalysis for Selective C(sp3)-O Cleavages of Phosphinates to Carbanions

We report a novel example of electro-mediated photoredox catalysis (e-PRC) in the reductive cleavage of C(sp³)-O bonds of phosphinates to alkyl carbanions. As well as deoxygenations, olefinations are reported which are <i>E</i>-selective and can be made <i>Z</i>-selective in a tandem reduction/photosensitization process where both steps are photoelectrochemically promoted. Spectroscopy, computation and catalyst structural variations reveal that our new naphthalene monoimide-type catalyst allows for a more intimate dispersive precomplexation of its radical anion form with the phosphinate substrate, facilitating a reactivity-determining C(sp³)-O cleavage. Surprisingly and in contrast to previously reported photoexcited radical anion chemistries, our conditions i) tolerate aryl chlorides/bromides and ii) do not give rise to Birch-type reductions.

Electro-mediated PhotoRedox Catalysis for Selective C(sp3)-O Cleavages of Phosphinates to Carbanions

We report a novel example of electro-mediated photoredox catalysis (e-PRC) in the reductive cleavage of C(sp³)-O bonds of phosphinates to alkyl carbanions. As well as deoxygenations, olefinations are reported which are <i>E</i>-selective and can be made <i>Z</i>-selective in a tandem reduction/photosensitization process where both steps are photoelectrochemically promoted. Spectroscopy, computation and catalyst structural variations reveal that our new naphthalene monoimide-type catalyst allows for a more intimate dispersive precomplexation of its radical anion form with the phosphinate substrate, facilitating a reactivity-determining C(sp³)-O cleavage. Surprisingly and in contrast to previously reported photoexcited radical anion chemistries, our conditions i) tolerate aryl chlorides/bromides and ii) do not give rise to Birch-type reductions.

Catalytic Reductive Cleavage of Poly(phenylene sulfide) using a Hydrosilane

The solvent-insoluble poly(phenylene sulfide) main chain was reductively cleaved by using triethylsilane as a hydrogen source under palladium/IcHex catalytic conditions. After the reaction, benzene and bis(triethylsilyl)sulfide as a sulfide source were formed efficiently. This method could be operated on a gram scale.

Chromium-Catalyzed Reductive Cleavage of Unactivated Aromatic and Benzylic C–O Bonds

The example of reductive cleavage of aromatic and benzylic C–O bonds by chromium catalysis is reported. This deoxygenative reaction was promoted by low-cost CrCl2 precatalyst combined with polymethylhydrogen siloxane as the mild reducing agent, providing a strategy in forming reduced motifs by cleavage of unactivated C–O bonds. A range of functional groups such as bromide, chloride, fluoride, hydroxyl, amino and alkoxycarbonyl can be retained in the reduction.