Mild reaction conditions are the advantage of the title reaction, which allows straightforward entry to a variety of ynamides starting from readily available 1,1‐dibromo‐1‐alkenes, which act as attractive alkynylating agents (see scheme; EWG=electron‐withdrawing group, DMF=N,N‐dimethylformamide).
Deep‐sea Diels–Alder : The asymmetric organocatalytic Diels–Alder reaction of cyclohexenones with aromatic nitroolefins can be carried out in seawater and brine. The reaction proceeds by an in situ enamine activation involving a one‐step concerted addition pathway (see scheme).
Easy breakage to open‐shells : The diamagnetic butterfly‐like dichalcogen complexes 1 (E=Se) and 2 (E=Te) with a {NiII2E2} core, undergo facile dissociation in solution via spin crossover to give the unprecedented mononuclear paramagnetic superselenide and supertelluride species 1′ and 2′ , respectively, along with the nickel(I) fragment [LNiI]; R=2,6‐diisopropylphenyl.
Rock trapping and exploration : Aziridinium bromide salts were discovered serendipitously during bromination of N,N‐dicarboxymethylated β‐amino alcohols. Regiospecific ring‐opening and rearrangement of the isolated, surprisingly stable aziridinium salts produces useful molecules including C‐functionalized oxomorpholines and α,β‐unsaturated amines.
Switchable molecules : The electronic configurations of the Fe center in trans‐[Fe(tzpy)2(NCS)2] in low‐spin, high‐spin, and LIESST states (LIESST=light‐induced excited spin‐state trapping) were confirmed by K‐ and L‐edge X‐ray absorption and magnetic measurements. The molecular structures at 40 K before and after irradiation are superimposed in the picture, which demonstrates a single‐crystal‐to‐single‐crystal transition by irradiation.
ONOO. is an important intermediate in the autoxidation of nitrogen monoxide by dioxygen. A formerly unknown red isomer of N2O4, ONOONO (see figure), formed in 2‐methylbutane at 113 K from nitrogen monoxide and dioxygen, is converted to O2NNO2 upon warming.
Going through the phases : The title reaction was found to proceed by an initial base‐mediated isomerization to allenyl esters and subsequent phase transfer catalyzed alkylation at the α position of the ester (see scheme).
Squashy cage : A flexible, spongelike, and reversible metal‐binding Cu2L2 cage that can adjust its internal space in response to pyrazine and its derivatives based on a recognition sequence of pyrazine, 2,5‐dimethylpyrazine, and 2‐methylpyrazine (see figure) is described.
Molecular versatility : Unusual reactivities such as hydrolysis, nucleophilic aromatic substitution, and addition reactions of human orotidine‐5′‐monophosphate decarboxylase are explained by crystal structures and involve a nucleophilic lysine residue that normally is expected to act solely as a general base (RP=phosphoribosyl, R=CO2H, CN, acetyl, N3, I; R′=OH, SH, acetyl, hydroxymethyl).
Base‐catalyzed activation of the C? F bond in the trifluoromethylazo‐substituted cyclic and acyclic alkanes provides a route to disubstituted azidotetrazoles. For example, the reaction of 1,2‐bis(trifluoromethylazo)ethane with four equivalents of NaN3 gave the alkyl‐bridged bis(5‐azido‐1H‐tetrazol‐1‐yl)‐1,2‐dimine, N,N′‐bis(5‐azido‐1H‐tetrazol‐1‐yl)‐1,2‐diiminoethane, in 75 % yield (see scheme).
High‐de‐hydride! A straightforward reaction between a magnesium silylamido/N‐heterocyclic carbene adduct and phenylsilane provides a {Mg4H6} cluster molecule that may be regarded as a combination of two magnesium dihydride and two magnesium monohydride moieties.
Monodentate DNA binding of [PtCl(dien)]+ (dien=diethylenetriamine) complexes may considerably affect the biophysical properties of DNA and consequently downstream cellular processes as a result of a large increase in the bulkiness of the nonleaving ligand by multiple methylation (see illustration).
Cascade reactions : Lewis acid catalyzed cascade reactions of 1,6‐diynes and 1,6‐enynes with arylvinylidenecyclopropanes produce polycyclic compounds and isopropylidene‐3,3‐diarylcyclobut‐1‐enylmethyl derivatives (see scheme) in good to high yields along with a PtCl2‐catalyzed cyclization and a Cu(OAc)2 ? H2O‐catalyzed Eglinton coupling reaction.
United in effort : The combined application of iminium (Im) and enamine (En) catalysts can effect a range of valuable asymmetric transformations including 1,2‐hydroamination, ‐hydro‐oxidation, and ‐amino‐oxidation of olefins (see picture). An enantioselective organocascade catalysis was also applied in the synthesis of a complex natural product.
Special delivery : Liposomal drug‐delivery systems in which prodrugs are activated specifically by disease‐associated enzymes have great potential for the treatment of severe diseases, such as cancer. A new type of phospholipid‐based prodrug has the ability to form stable small unilamellar vesicles (see picture). Activation of the prodrug vesicles by the enzyme sPLA2 initiates a cyclization reaction, which leads to the release of the drug.
The right fit : Plasmid DNA molecules show chirality‐dependent interaction with gold surfaces modified by L and D N‐isobutyrylcysteine. Relaxed DNA molecules have a stronger interaction and adsorption on the L surface, while their counterparts on the D surface maintain a supercoiled conformation, indicating a weak interaction (see picture).
Ab initio computations performed on LaF3?Arn (n=1–21) complexes allow a quantification of the short‐range many‐body interactions arising in the argon matrix. It is shown that the molecular properties of LaF3 are strongly influenced by the embedding medium. The largest investigated cluster, LaF3?Ar21, resembles an hcp structure with the LaF3 molecule occupying the central substitutional site (see figure).
Economical atoms : 2‐Cyclopenten‐1‐ones, 5‐alkylidenefuran‐2(5 H)‐ones and indan‐1‐ones have been synthesized by atom‐economic reductive cyclocarbonylation of internal alkynes with carbon monoxide catalyzed by [{RhCl(CO)2}2]/CO(NH2)2 in the presence of water (see scheme).
Cobalt and battery charge : Porous Co3O4 with a hexagonal sheetlike structure has been synthesized through precursor Co(OH)2 hexagonal nanosheets (see figure). The as‐prepared nanosheets exhibit excellent Li‐battery performance with a good cycle life and high capacity (1450 mAh g?1).
