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The new quasi-two-dimensional title compound is prepared by annealing mixtures of SrFeO3 (obtained by sintering SrCO3 and Fe2O3 at 1000 °C for 24 h) and polyvinylidene fluoride under N2 flow at 400 °C for 48 h, followed by heating the product with CaH2 under Ar atmosphere to 280 °C for 48 h.

The novel and one-pot synthesis of 5-hydroxyl hydantoins from Ugi five-component condensation procedures is reported. The transformation was promoted via a microwave heating method and provided 5-hydroxyl hydantoins in workable yields, representing a direct approach to this synthetically challenging and biologically interesting pharmacophore.

A kinetically controlled Z-selective cross-metathesis yielding α,β-unsaturated esters is presented.

A rhodium-catalyzed cross-coupling of aryl and aliphatic quinolinyl ketones with boronic acids has been developed. Proceeding via quinoline-directed carbon–carbon σ bond activation, the transformation demonstrates tolerance of a range of functional groups on both the ketone and aryl boronic acid substrates, providing good to excellent yields of the new ketones, particularly those containing electron-withdrawing substituents. Catalyst reactivity is dependent on quinolinyl ketone substrates, with alkyl ketones requiring Rh(PPh3)3Cl instead of the more reactive [Rh(C2H4)2Cl]2. With the use of K2CO3 as an additive, methyl boronic acid is also a competent substrate, giving rise to an unprecedented methylation technique.

A new method for the decarboxylative coupling of alkyl N-hydroxyphthalimide esters (NHP esters) with aryl iodides is presented. In contrast to previous studies that form alkyl radicals from carboxylic acid derivatives, no photocatalyst, light, or arylmetal reagent is needed, only nickel and a reducing agent (Zn). Methyl, primary, and secondary alkyl groups can all be coupled in good yield (77% ave yield). One coupling with an acid chloride is also presented. Stoichiometric reactions of (dtbbpy)Ni(2-tolyl)I with an NHP ester show for the first time that arylnickel(II) complexes can directly react with NHP esters to form alkylated arenes.

The gold-catalyzed enantioselective hydroazidation and hydroamination reactions of allenes are presented herein. ADC gold(I) catalysts derived from BINAM were critical for achieving high levels of enantioselectivity in both transformations. The sense of enantioinduction is reversed for the two different nucleophiles, allowing access to both enantiomers of the corresponding allylic amines using the same catalyst enantiomer.

An improved method for the reductive coupling of aryl and vinyl bromides with alkyl halides that gave high yields for a variety of substrates at room temperature with a low (2.5 to 0.5 mol %) catalyst loading is presented. Under the optimized conditions, difficult substrates, such as unhindered alkenyl bromides, can be coupled to give the desired olefins with minimal diene formation and good stereoretention. These improved conditions also worked well for aryl bromides. For example, a gram-scale reaction was demonstrated with 0.5 mol % catalyst loading, whereas reactions at 10 mol % catalyst loading completed in as little as 20 minutes. Finally, a low-cost single-component pre-catalyst, (bpy)NiI2 (bpy=2,2′-bipyridine) that is both air- and moisture-stable over a period of months was introduced.

The efficient method for the cycloaminomethylation of glycoluril to yield 2,6-ditert-butylhexahydro-1H,5H-2,3a,4a,6,7a,8a-hexaazacyclopenta[def]fluorene-4,8-dione is described. The material is synthesized employing water as the solvent, and is isolated by filtration. This is an improvement over the previous reported synthetic method, which relied on the use of samarium trichloride catalysis, as well as silica gel column chromatographic purification to obtain the target product.

A diastereoselective auxiliary-mediated vinylation/[1,2]-Brook rearrangement/vinylogous Michael cascade of silyl glyoximide, vinylmagnesium bromide, and nitroalkenes is described. The reaction occurs with complete regio- and diastereocontrol in good yield. The diastereoselectivity is induced by a rare instance of 1,7-chirality transfer that is hypothesized to arise from a trans-multihetero-decalin transition state.

We exploit the Buchner reaction to access 1,2-disubstituted cyclohexadiene synthons (norcaradienes), which participate in H2O-accelerated cycloaddition with dieneophiles to provide cyclopropyl-fused [2.2.2]-bicyclooctene derivatives in good yields. Regioisomeric mixtures can be kinetically separated by exploiting different reaction rates in Diels–Alder reactions. Meso-Diels–Alder products may be enantioselectively desymmetrized, providing highly substituted cyclohexanes with up to seven contiguous stereocenters.

The development of a functional disulfide, FmSSPy-A (Fm = 9-fluorenylmethyl; Py = pyridinyl), is reported. It can effectively convert small molecule and protein thiols (−SH) to form −S-SFm adducts under mild conditions. This method allows for a H2S-free and biomimetic protocol to generate highly reactive persulfides (in their anionic forms). The high nucleophilicity of persulfides toward a number of thiol-blocking reagents is also demonstrated. The method holds promise for further understanding the chemical biology of persulfides and S-sulfhydration.

Over the past decades, there is increasing information about synthesis, characterization and applications of metal complexes including quinoxaline derivative metal complexes. The focus of the review is emphasized on synthesis, characterization, structural analysis, theoretical calculations and biological studies of quinoxaline derivative metal complexes. These types of review provide unique platform for systematically studying the various quinoxaline derivative metal complexes synthesized so far and their characterizations. We have also highlighted the synthetic strategies developed to synthesize metal complexes. Several characterizations which are not covered in part-I like CD-spectroscopy are also included in this review paper. This review is also a focus of the reports on the structural aspects that the quinoxaline based ligands plays on compounds reported in last seven years. Furthermore in this review the current progress of research in the field of quinoxaline derivative metal complexes from 2007 to end of 2014 is summarized. The structure was confirmed by single crystal x-ray diffraction studies. An overview of application of quinoxaline derivative metal complexes is also presented. Structural elucidation using Density Functional Theory (DFT) and Time Dependent-Density Functional Theory (TD-DFT) are included. In addition to various biological studies included in the previous part, cytotoxicity, photo cytotoxicity studies, antitubercular studies, insulin mimetic activity, anti-trypanosome cruzi activity, anti-proliferative activities are included.

An organocatalytic three-component reductive coupling reaction between dimethyl phosphite, benzylidene pyruvates, and aldehydes is reported. A chiral triaryliminophosphorane catalyst promotes Pudovik addition, which is followed by phospha-Brook rearrangement to transiently generate enolates that are trapped stereoselectively by aldehydes. This reductive coupling provides vicinal polyfunctionalized stereocenters from readily available prochiral starting materials with excellent diastereoselectivity, enantioselectivity, and yield.

Dynamic kinetic resolutions of α-stereogenic-β-formyl amides in asymmetric 2-aza-Cope rearrangements are described. Chiral phosphoric acids catalyze this rare example of a non-hydrogenative DKR of a β-oxo acid derivative. The [3,3]-rearrangement occurs with high diastereo- and enantiocontrol, forming β-imino amides that can be deprotected to the primary β-amino amide or reduced to the corresponding diamine.

A new bismuth-containing layered perovskite of the Ruddlesden–Popper type, K2.5Bi2.5Ti4O13, has been prepared by solid-state synthesis. It has been shown to hydrate to form stoichiometric K2.5Bi2.5Ti4O13·H2O. Diffraction data show that the structure consists of a quadruple-stacked (n = 4) perovskite layer, with potassium ions occupying the rock salt layer and its next-nearest A site. The hydrated sample was shown to remove the offset between stacked perovskite layers relative to the dehydrated sample. Computational methods show that the hydrated phase consists of intact H2O molecules in a vertical “pillared” arrangement bridging across the interlayer space. Rotations of H2O molecules about the c axis were evident in molecular dynamic calculations, which increased in rotation angle with increasing temperature. In situ diffraction data for the dehydrated phase point to a broad structural phase transition from orthorhombic to tetragonal at ∼600 °C. The relative bismuth-rich composition in the perovskite bloc...

The development of a rhodium catalyst for endo- and enantioselective hydroacylation of ortho-allylbenzaldehydes is reported. A catalyst generated in situ from [Rh(COD)Cl]2, (R)-DTBM-SEGPHOS, and NaBARF promotes the desired hydroacylation reactions and minimizes the formation of byproducts from competitive alkene isomerization and ene/dehydration pathways. These rhodium-catalyzed processes generate the 3,4-dihydronaphthalen-1(2H)-one products in moderate-to-high yields (49–91%) with excellent enantioselectivities (96–99% ee).

A new highly stereoselective and metal-free multicomponent coupling reaction between isatins and aldehydes with dialkyl phosphite as an economical reductant is reported.

An enantioselective synthesis of the indole diterpenoid natural product paspaline is disclosed. Critical to this approach was the implementation of stereoselective desymmetrization reactions to assemble key stereocenters of the molecule. The design and execution of these tactics are described in detail, and a thorough analysis of observed outcomes is presented, ultimately providing the title compound in high stereopurity. This synthesis provides a novel template for preparing key stereocenters in this family of molecules, and the reactions developed en route to paspaline present a series of new synthetic disconnections in preparing steroidal natural products.

The title heterocycles can serve as carbostyril mimics with applications for pharmaceuticals, or as novel switchable fluorophores.

The oxidation of arenes by the reagent phthaloyl peroxide provides a new method for the synthesis of phenols. A new, more reactive arene oxidizing reagent, 4,5-dichlorophthaloyl peroxide, computationally predicted and experimentally determined to possess enhanced reactivity, has expanded the scope of the reaction while maintaining a high level of tolerance for diverse functional groups. The reaction proceeds through a novel “reverse-rebound” mechanism with diradical intermediates. Mechanistic insight was achieved through isolation and characterization of minor byproducts, determination of linear free energy correlations, and computational analysis of substituent effects of arenes, each of which provided additional support for the reaction proceeding through the diradical pathway.

Mass spectrometry is a powerful tool in natural product structure elucidation, but our ability to directly correlate fragmentation spectra to these structures lags far behind similar efforts in pep...

The enantiomers of the natural product cycloprodigiosin were prepared using an expedient five-step synthetic sequence that takes advantage of a Schollkopf–Barton–Zard (SBZ) pyrrole annulation with a chiral isocyanoacetate and a nitrocyclohexene derivative. Using chiral HPLC and X-ray crystallographic analyses of the synthetically prepared material and natural isolate (isolated from the marine bacterium Pseudoalteromonas rubra), naturally occurring cycloprodigiosin was determined to be a scalemic mixture occurring in an enantiomeric ratio of 83:17 (R)/(S) at C4′.

The Ligand Polyhedral Model (LPM) is applied to the carbonyl scrambling observed on the NMR timescale for the two cluster carbonyls [Rh4(CO)12] and [Rh6(CO)16]. For [Rh4(CO)12] the NMR data is completely consistent with the libration of the Rh4 central core about a C3 – rotational axis within the icosahedral shell of twelve CO ligands leading to a single-step concerted exchange process. Rotation of the Rh4 unit is also found to lead to the formation of a new all terminally bonded isomer which retains the icosahedral shell of CO ligands. Importantly, this new isomer does not have the [Ir4(CO)12] structure which is known to possess an cube-octahedral ligand shell. With [Rh6(CO)16] and its substituted derivative [Rh6(CO)15L] exchange is considered to take place via a polyhedral inter-conversion in which the external tetra-capped truncated tetrahedral shell of carbonyl ligands observed in the ground-state undergoes rearrangement first to the 2 : 6 : 6′ : 2 complementary geometry and then returns to the ground-state structure. This leads to a single-step fully concerted CO exchange. The LPM approach also provides an understanding of the variation of activation energies observed in going from [Rh4(CO)12] to [Rh6(CO)16] and of the driving force to the fluxional process.

Evaluation of the protecting groups leads to the identification of N-trityl-5,5-diethoxy protected 1,1,1-trifluoropent-3-yn-2-imine as suitable precursors for the cyclization with aryl and alkyl substituted methylamines and subsequent deprotection to 2-substituted picolinaldehydes.

The catalyst is found to effectively promote the boron incorporation with nonterminal selectivity and adjacent to π-systems even in substrates where the alkene is at a remote position.

The direct catalytic functionalization of traditionally unreactive C–H bonds is an atom-economic transformation that has become increasingly important and commonplace in synthetic applications. In general, 2nd and 3rd row transition metal complexes are used as catalysts in these reactions, whereas the less costly and more abundant 1st row metal complexes have limited utility. This Perspective article summarizes progress from our laboratory towards understanding the fundamental issues that complicate the use of Ni complexes for catalytic C–H bond functionalization, as well as approaches to overcoming these limitations. In practice it is found that Ni complexes can functionalize C–H bonds by processes that, to date, have not been observed with the heavier metals. An example is provided by the catalytic stannylation of C–H bonds with tributylvinyltin, Bu3SnCHCH2, which produces ethylene as a by-product.

A chiral N-heterocyclic carbene-catalyzed a3 d3-umpolung addition of α,β-enals to racemic α-keto esters gives access to γ-butyrolactones with high regio-, diastereo-, and enantiocontrol.

The series of new heterometallic aqueous nanoscale Ga/In tridecameric clusters C6H96Ga11.8In1.2N15 O99, C6H96Ga10.27In2.73N15 O99, C6H96Ga10.3In2.7N15 O99, C6H96Ga9.1In3.9N15 O99, C6H96Ga7.7In5.3N15 O99, and C6H96Ga7In6N15 O99 is synthesized from Ga(NO3)3 and In(NO3)3 hydrates dissolved in MeOH in the presence of N-nitrosodibutylamine (evaporation of the solvent in air at room temperature, 14 d, 20—63% yield).

Organouranium complexes containing uranium–carbon σ-bonds have been highly sought after since the initial exploration of these complexes during the 1950s. Since this time, a variety of uranium starting materials have been developed and alkylating reagents used in order to generate such species. Trivalent uranium alkyl compounds have recently moved past using the bis(trimethylsilyl)methyl ligand with the use of larger ancillary hydrotris(pyrazolyl)borate ligands. The uranium(IV) congeners are dominated by cyclopentadienyl ligands, but recent developments have shown that amides, alkoxides, and phosphines are also suitable ligand frameworks for supporting such species. A family of uranium(IV) alkyls formed via cyclometallation and neutral homoleptics have also been described. Highly reactive uranium(V) and (VI) alkyl complexes have recently been synthesized at low temperatures. The representative studies highlighted herein have helped to pioneer the field of organouranium alkyl chemistry.

Following a review on thermodynamic data on both α-B and β-B, the relative stability of the allotropes is determined as a function of temperature by heat capacity measurements.

The reaction of acyclic 1,2-diketones with electron deficient aryl aldehydes proceeds with high regioselectivity which is controlled by the catalyst used.

Pd(Tfa)2-catalyzed arylation, heteroarylation and cycloalkylation of benzoquinone is performed in water as well as in acetone.

A convenient synthesis of α-chiral sulfinates from readily available precursors has been accomplished via the corresponding heterocyclic thioethers and sulfones. Treatment of the sulfinates with hydroxylamine sulfonate in aqueous solution provides α-C-chiral primary sulfonamides in good yield (14 examples) with retention of stereochemical purity.

The dynamic kinetic resolution of β-halo α-keto esters via an asymmetric cross-benzoin reaction is described. A chiral N-heterocyclic carbene catalyzes the umpolung addition of aldehydes to racemic α-keto esters. The resulting fully substituted β-halo glycolic ester products are obtained with high levels of enantio- and diastereocontrol. The high chemoselectivity observed is a result of greater electrophilicity of the α-keto ester toward the Breslow intermediate. The reaction products are shown to undergo highly diastereoselective substrate-controlled reduction to give highly functionalized stereotriads.

Optically active cyclobutanols are obtained via cyclization of alkynones with arylboronic acids by using a chiral bicyclooctadiene ligand.

Six structural isomers containing four structural units of PbSe and four structural units of NbSe2 of compositions [(PbSe)1.14]4[NbSe2]4, [(PbSe)1.14]3[NbSe2]3 [(PbSe)1.14][NbSe2]1, [(PbSe)1.14]3[NbSe2]2 [(PbSe)1.14][NbSe2]2, [(PbSe)1.14]2[NbSe2]3 [(PbSe)1.14]2[NbSe2]1, [(PbSe)1.14]2[NbSe2]2 [(PbSe)1.14] [NbSe2]1[(PbSe)1.14] [NbSe2]1, and [(PbSe)1.14]2[NbSe2] [(PbSe)1.14][NbSe2]2 [(PbSe)1.14][NbSe2] are prepared from modulated elemental precursors by annealing at 450 °C for 1 h in a nitrogen atmosphere.

A stable visible-light driven photocatalyst (λ ≥ 450 nm) for H2O oxidation is prepared by Rh substitution into the pyrochlore Y2Ti2O7 to a maximum level of 2% by stoichiometric solid state reactions of Y2O3, TiO2, and Rh2O3 under air (Pt foil lined alumina boat, 1300 °C, 2 d).

Thin films of the new title intergrowth compound consisting of a bilayer of SnSe and TiSe2 trilayer are prepared by self-assembly from a precursor containing modulated layers of Sn-Se and Ti-Se, which is synthesized by deposition of elemental layers (annealing at 350 °C).

A one-pot four-step multi-reaction process involving a thermal Overman rearrangement, a tandem metathesis reaction, and a Diels—Alder reaction is developed for the diastereoselective synthesis of aminobicyclononanes and -decanes with up to five stereogenic centers.

A mild regioselective and stereoselective direct formal SN2′ thioetherification of allylic alcohols is developed.

An efficient reaction manifold for the preparation of C3/C5-diarylimidazo[1,2-a]pyrazines through sequential C3 and C5 direct arylation is disclosed. The two distinct palladium catalyst systems showcased herein are compatible with a wide variety of aryl and heteroaryl bromides and are also operative in a one-pot, twofold C–H functionalization event.