Buckle up! The dimerization of small fluorescent guests is strongly enhanced in presence of a cyclodextrin host. The host cavity acts like a belt to assist the self‐assembly of guests (see picture). Small variations in the guest structure have significant influence on the stability and geometry of the aggregates.
Protein deposition frequently occurs as inclusion bodies (IBs) during heterologous protein expression in E. coli. The structure of these E. coli IBs of the prion‐forming domain from the fungal prion HET‐s is the same as that previously determined for fibrils assembled in vitro, and show prion infectivity. These results demonstrate that the IBs of HET‐s(218–289) are amyloids.
Economical approach : The first organocatalytic asymmetric intramolecular hydroarylation of phenol‐ and aniline‐derived enals offers one of the most straightforward and atom‐economic approaches to enantioriched chromans and tetrahydroquinolines (up to 96 % ee; see scheme).
Reaction rates from polarized spectroscopy : A new method based on ultrafast pump–probe polarization spectroscopy enables the measurement of the ground‐ and excited‐state reaction rates for self‐exchange processes. The technique was used to study double hydrogen transfer in porphycene and its derivatives (see figure).
Bridging pyrrole and selenophene chemistries : Molecular assemblies have been developed that allow scrutiny of the electronic communication between pyrrole and selenophene nuclei. Divergent syntheses of 2‐(selenophen‐2‐yl)pyrroles and their N‐vinyl derivatives from available 2‐acylselenophenes and acetylenes in a one‐pot procedure have been devised (see scheme), which provide access to these exotic heterocyclic ensembles.
Finding the few : Cell‐surface proteins are useful disease biomarkers, but current high‐throughput methods are limited to detecting cells expressing more than several hundred proteins. Enzymatic amplification in microfluidic droplets (see picture) is a high‐throughput method for detection and analysis of cell‐surface biomarkers expressed at very low levels on individual human cells. Droplet optical labels allow concurrent analysis of several samples.
Direct visualization of photoinduced tunneling charge transfer (TCT) in an Au5/para‐aminothiophenol (PATP)/Ag6 junction in which Au and Ag clusters form the first and second layer, respectively, is provided by the charge difference density (see picture; green and red stand for holes and electrons, respectively).
Amino sulfonamide catalyst : A distal proton of the axially chiral amino sulfonamide (S)‐ 1 realized the opposite diastereoselectivity in Mannich and cross‐aldol reactions compared with that observed in proline‐catalyzed reactions. The reactions catalyzed by (S)‐ 1 proceeded smoothly to give the anti‐Mannich and syn‐aldol adducts in excellent enantioselectivity (see scheme).
No protection? A unique, albeit fairly specialized, example of what promises to be a useful retrosynthetic consideration for those designing complex π‐molecular systems, namely, using conformation as a protecting group to shield a given reactive site in lieu of protecting‐group manipulation, is described (see scheme).
Osmabenzenes can be easily synthesized from two η2‐coordinated olefin osmacycles in the presence of benzonitrile by means of facile hydrogen‐transfer conversions (see graphic). Mechanisms for the formation of osmabenzenes are proposed based on DFT calculations.
Assembly language : The programmed sequences of stereochemical building blocks lead to novel biomimetic helices. The rational design approach offers new possibilities for creating periodic secondary structures.
