′I′ is all the hype : A twofold excess of iodoarene in the title reaction leads to ortho‐quinols in good yields, whereas organocatalytic versions of this reaction enable subsequent epoxidation in a regio‐ and diastereoselective fashion. Chiral iodobiarenes led to enantioselectivities up to 50 % ee. m‐CPBA=meta‐chloroperoxybenzoic acid.
Constructing α‐stereogenic amides and ketones : The highly regioselective and enantioselective conjugate addition of 1,3‐dicarbonyl compounds to 1,4‐dicarbonyl but‐2‐enes has been developed with the chiral bicyclic guanidine as catalyst (ee values up to 97 %; see scheme).
Basic catalysis! The basic properties of hydrotalcites (see picture) make them attractive for numerous catalytic applications. Probing the basicity of the catalysts is crucial to understand the base‐catalysed processes and to optimise the catalyst preparation. Various parameters can be employed to tune the basic properties of hydrotalcite‐based catalysts towards the basicity demanded by each target chemical reaction.
You oughta use water : Broad functional‐group (FG) tolerance was observed for the title coupling of aryl halides (X=Cl, Br, I) and aryl boronic acids to give biaryl compounds with up to 94 % ee. The chiral imidazoindole phosphine–palladium catalyst supported on an amphiphilic polystyrene–poly(ethylene glycol) (PS–PEG) resin could be recycled readily.
Another way to dienes : The ruthenium‐catalyzed 6‐endo‐cycloisomerization of 1,5‐enynes gives the corresponding 1,3‐cyclohexadienes in high to excellent yields. This novel synthetic and catalytic method constitutes another way to selectively prepare 1,3‐cyclohexadienes, this cyclic diene skeleton being a core subunit in many natural products and a useful building block for a variety of organic transformations.
Brilliance of terbium : Heterodimeric conjugates of trimethoprim covalently linked to sensitized terbium chelates bind to Escherichia coli dihydrofolate reductase fusion proteins with nanomolar affinity (see picture). Terbium luminescence enables sensitive and time‐resolved detection of labeled proteins in vitro and on the surface of living mammalian cells.
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).
Round and round : Covalently bound spokes induce an efficient template‐directed cyclization towards a rigid molecular wheel (see figure) and afford dramatically increased shape‐persistence properties compared with non‐strutted macrocycles.
Positive discrimination : Chemo‐ and regioselective palladium‐catalyzed cycloetherification of allendiols, namely β,γ‐ and γ,δ‐allendiols, may occur by judicious choice of palladium‐catalyzed conditions owing to their potential ability to discriminate between both nucleophilic sites (see scheme).
Low‐temperature electrochemical oxidation of thioglycosides gave glycosyl triflates from which glycosyl sulfonium ions were produced (see scheme). The latter were characterized by NMR spectroscopy and cold‐spray mass spectrometry as a mixture of α‐ and β‐isomers (45:55). The α‐glycosyl sulfonium ion exhibited higher reactivity than the β‐glycosyl sulfonium ion in the reaction with methanol, which gave a mixture of α‐ and β‐methyl glycosides (41:59).
Trapped! Mesopolymer‐entrapped Pt nanoparticles serve as an efficient catalyst for the hydrogenation of benzaldehydes in water at ambient temperature. In comparison with the commercial Pt/alumina catalyst, the Pt/FDU‐14 catalyst shows superior performance in the hydrogenation reaction. The catalyst afforded high turnover frequencies and was reusable more than nine times without loss of activity or selectivity.
A rationally designed oligomerization inhibitor interacts with early intermediate assemblies of amyloid‐β polypeptide (Aβ) through the aromatic elements and inhibits their assembly into the toxic oligomers that cause Alzheimer's disease by a unique Cα‐methylation β‐breakage strategy. The electrostatic potential of the low‐energy conformation of the dipeptide inhibitor bound to Aβ is shown.
A microreactor of hollow polymeric microspheres with Pd nanoparticles immobilized in its wall is designed for hydrogenation of olefins under organic/aqueous biphasic catalysis. The microreactor has an ability to encapsulate and concentrate olefins within the vacancy of the hollow microspheres in the aqueous phase, and therefore hydrogenation within the microreactors runs efficiently with concentrated reactants under organic/aqueous biphasic condition (see scheme).
Bleomycin mimics : Efficient oxidative double‐strand DNA cleavage has been achieved with multinuclear non‐heme iron complexes (see scheme). These complexes therefore represent model compounds that mimic the mode of action of the anti‐tumor drug bleomycin.
