Tea time! Gold nanoparticles (GNPs) could be readily prepared by a general strategy involving the reduction of aqueous HAuCl4 in the presence of traditional Chinese medicines (TCMs). Spheroidal and triangular gold nanoparticles were observed depending on the TCM used. The strategy exemplified the universal application of plant bioresources for the synthesis of GNPs and catalytic purposes.
Synergy in synthesis : Strategic consideration of metathesis and Suzuki–Miyaura (SM) cross‐coupling for C? C bond‐formation processes has opened up new and “green” synthetic routes to various complex targets. The use of this synergistic combination for the synthesis of supramolecular ligands, polyaromatic compounds, and complex natural products is covered in this Focus Review.
It′s a fine line : Methyltrioxorhenium(VII) (MTO) readily forms 1:1 adducts with several N‐(salicylidene)aniline derived Schiff bases. Steric and electronic effects of the ligands play a major role when it comes to stability and catalytic activity. Good donors on the Schiff base ligands, in general, lead to shorter Re? O(Schiff base) bridges and lower catalytic activity, while it is the opposite for acceptor ligands on the Schiff bases.
“ Quat's” the story? N‐Aryl amides are effective directing/activating groups for chlorosilane Lewis acids. This aspect has been exploited for the development of the first simple and general method for the highly enantioselective Pictet–Spengler reaction of ketimines derived from α‐ketoamides leading to quaternary α‐amino acid derivatives (see scheme).
Playing the sax : The enantioselective total syntheses of (?)‐ and (+)‐decarbamoyloxysaxitoxin (doSTX) and (+)‐saxitoxin (STX) are reported. A new methodology was developed for the synthesis of STXs, featuring discriminative reduction of the nitro group and N? O bond in nitroisoxazolidine.
“My first experiment was preparation of proline‐derived chiral ligands for asymmetric alkylation. My favorite subjects at school were history and English…?.” This and more about Keisuke Suzuki can be found on page 2635.
Alkynes of reactions : Recent breakthroughs in metal‐catalyzed alkyne reactions, which expand the synthetic utility of alkynes, have been achieved. These approaches broaden the range of alkynes that are accessible by C? N and C? C bond‐forming reactions and demonstrate that the use of bifunctional heterobimetallic catalysts can lead to new reactivity and excellent enantioselectivity (see scheme).
The identification and control of a critical stage of polyaniline “nanotube” self‐assembly is presented, namely the granular agglomeration or growth onto nanorod templates. When the synthesis pH is held above 2.5, smooth insulating nanorods exhibiting hydrogen bonding and containing phenazine structures are produced, while below pH 2.5, small 15–30 nm granular polyaniline nanoparticles appear to agglomerate onto the available nanorod surface, apparently improving conductivity of the resulting structures by three orders of magnitude. This finding affects both fundamental theories of polyaniline nanostructure self‐assembly and their practical applications.
Intelligent design : The total synthesis of the cytotoxic (?)‐FR182877 relies on 1) tandem Diels–Alder reactions to close rings A–D (see scheme), 2) a palladium‐mediated 7‐exo‐trig reaction, and 3) an iridium‐mediated isomerization followed by epimerization and stereoselective reduction.
Silica scaffolding : By employing functionalized mesoporous SBA‐15 silica, novel fluorescent cruciform‐silica hybrid materials are generated which preserve the desirable solution properties of cruciforms in the solid state for potential use in sensory schemes.
Simple addition : Copper(II) aqua complex 1 can be prepared in a one‐pot synthesis and is self‐assembled by H‐bond interactions. Complex 1 is shown to accelerate the nitroaldol reaction on water, which is a heterogeneous process, requiring no additive or base, and 1 can be recycled without loss of activity.
Three attractions in one cage : Various magnetic networks are formed in the three polymorphs of an organic magnet, BBTDA(=benzo[1,2‐d:4,5‐d′]bis[1,3,2]dithiazole)?GaBr4. The three phases show quite different magnetic behaviors in spite of having the same chemical formula. Their magnetic differences originate from the relative configuration of the neighboring organic radical molecules in their crystals.
Pass the salt, please! State‐of‐the‐art computations indicate that the stacking complex of a guanine quartet and an adenine quartet (G4A4) can function as a potent ditopic receptor for NaCl in aqueous solution (see picture; Na+, Cl? yellow, O red, N blue, C black, H white).
Excellent couplings : Recent developments in the metal‐catalyzed C? H activation of sp3 centers in an α position relative to an amine nitrogen atom are presented. Their reaction with alkenes to give alkylamines (hydroaminoalkylation) is also summarized (see general scheme).
Conditional cleavage : Photochemical S? N bond cleavage of the Zn2+ complex of N‐dansylcyclen (ZnL2) in aqueous solution was investigated. Moreover, photolysis of ZnL2 (see scheme) facilitated photoreversion of cis,syn‐thymine photodimer (T[c,s]T).
Always on the move : Molecular dynamics of perylene cores in columnar structures influences the processability and self‐healing of these materials. A combination of X‐ray scattering and advanced solid‐state NMR methods show that these systems have restricted angular mobility of the cores even in the frozen phase, and a cooperative spiral type of motion in the liquid crystalline phase (see picture).
Last but not least : A simple molecular redox system is used to split water into hydrogen and oxygen photochemically. Two separate photolyses are combined to a cyclic process (see scheme). Osmocene ([Cp2OsII] with Cp?=C5H5?) serves as photocatalyst.
