The fungus Rhizopus microsporus …? ; shown in the micrograph on the cover picture, harbors the endosymbiotic bacteria Burkholderia rhizoxinica that produces the antimitotic polyketide macrolide rhizoxin (see structure). In their Communication on page 5001 ff. , C. Hertweck and co‐workers show that the enzyme rhizoxin polyketide synthase is uniquely capable of introducing a β branch (highlighted by the magnifying glass) by a Michael‐type addition of a malonyl unit to an acryloyl intermediate.
A spin‐crossover cluster with the {FeII4O4} core structure is presented by D. Y. Wu, O. Sato et al. in their Communication on page 1475 ff. The cluster is synthesized by self‐assembly and shows an abrupt spin transition, giving two high‐spin and two low‐spin states. It exhibits complete light‐induced excited spin‐state trapping effects. Importantly, synergy effects between the magnetic interaction and spin transition operate in the cluster.
Are you in? Bimetallic PtRu nanoparticles have been selectively confined inside or deposited outside carbon nanotubes (see picture). The confined nanoparticles display significantly higher selectivity and catalytic activity in hydrogenation reactions.
Wrong handedness? No problem! K.‐H. Ernst et al. describe in their Communication on page 4065 ff. how the chirality of single adsorbates can be switched into the opposite enantiomeric state. By using inelastically tunneling electrons from the tip of a scanning tunneling microscope in an ultra‐high vacuum, certain molecular vibrations are excited that, in turn, cause different actions such as hopping, rotation, and chirality conversion at the surface.
When one ring is not enough : A new double cyclization of stilbene derivatives results in benzo[b]fluorenes via dihydronaphthalenes. The presence of a selenium electrophile and a Lewis acid are crucial for the formation of the C? C bonds.
Efficient couplings using equimolar quantities of each coupling partner and multiple C? H bond arylation reactions are achieved with an Ir‐based catalytic system for the C? H bond arylation of electron‐rich heteroarenes with iodoarenes to construct extended π‐systems. The dramatic ligand effect on reaction efficiency leads to the discovery that Crabtree's catalyst (see scheme) is the optimal catalyst precursor.
A Powerful Luminophore that comprises a centered pyrene acceptor with peripheral amine multidonors is described by J. S. Kim and co‐workers in their Communication on page 2522 ff. The electrochemiluminescence (ECL) efficiency and radical stability of pyrene, a poor ECL luminophore, is markedly improved as the number of peripheral multidonor units is increased in a series of compounds. The ECL enhancement was rationalized by photophysical and electrochemical studies, and theoretical calculations.
A variety of tertiary silanes , even those with functional substituents, undergo an unprecedented iron‐catalyzed dehydrogenative coupling (see scheme) in a convenient approach to disilanes, including unsymmetrical disilanes and polymers with Si? Si bonds in the backbone. Consideration of the catalytic reaction pathway revealed the intermediacy of a hydrido(disilyl)iron(IV) complex.
Unstable? We're able! 1,n‐Glycols serve as synthetic equivalents to unstable dialdehydes in two‐directional carbonyl allylation from the alcohol oxidation level under iridium‐catalyzed transfer hydrogenation conditions. Iterative asymmetric allylation employing 1,3‐propanediol enables the rapid assembly of protected 1,3‐polyol substructures with exceptional levels of stereocontrol.
Undue influence : N‐heterocyclic carbenes (NHCs) were found to reduce the strength of the B? H bonds of borane by a surprisingly large amount upon the formation of NHC–BH3 complexes. This property was exploited in the development of a suite of NHC–borane complexes for the reduction of xanthates in radical‐mediated Barton–McCombie‐type deoxygenation reactions (see scheme). AIBN=azobisisobutyronitrile, Bn=benzyl.
An sp 2 /sp 3 get‐together : A novel and efficient method can be used to synthesize 3,3‐disubstitued oxindoles by the direct intramolecular oxidative coupling of an aryl C? H and a C? H center (see scheme; DMF=N,N‐dimethylformamide).
Hierarchical semicrystalline block copolymer nanoparticles are produced in a segmented gas‐liquid microfluidic reactor with top‐down control of multiscale structural features, including nanoparticle morphologies, sizes, and internal crystallinities. Control of multiscale structure on disparate length scales by a single control variable (flow rate) enables tailoring of drug delivery nanoparticle function including release rates.