LiCl‐Mediated Preparation of Functionalized Benzylic Indium(III) Halides and Highly Chemoselective Palladium‐Catalyzed Cross‐Coupling in a Protic Cosolvent

Sensitive functional groups such as COR, CHO, or CH₂OH can be present in benzylic indium reagents prepared by the direct insertion of indium in the presence of LiCl. These reagents undergo palladium‐catalyzed cross‐coupling reactions in the presence of a protic cosolvent after activation with iPrMgCl⋅LiCl (see scheme). Remarkable chemoselectivities are achieved by using various electrophiles containing NH or OH groups.

     

Highly Enantioselective Pictet–Spengler Reactions with α‐Ketoamide‐Derived Ketimines: Access to an Unusual Class of Quaternary α‐Amino Amides

“ 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).

     

Darstellung und Eigenschaften von Ti-substituierten N-Heterocyclen

Preparation and Properties of Ti-substituted N-Heterocycles The compounds (x = 2 to 6) have been prepared by transamination of Ti(NMe₂)₄ with the heterocyclic amines and have been characterised by elemental analyses and ¹H NMR and IR spectroscopy. The dependence on both x and n of the thermal decomposition has been studied for the series and . The results can be interpreted in terms of the steric strain of the R₂N and substituents. Apart from the piperidido groups none of the ligands exhibit protective group properties comparable to the R₂N groups.     

Water Splitting by Light with Osmocene as Photocatalyst

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 ([Cp₂Os^II] with Cp^?=C₅H₅^?) serves as photocatalyst.

     

Potassium tert‐Butoxide‐Catalyzed Dehydrogenative Si?O Coupling: Reactivity Pattern and Mechanism of an Underappreciated Alcohol Protection

As simple as it gets! Potassium tert‐butoxide alone catalyzes the direct dehydrogenative Si? O coupling of several synthetically important silanes with 1°, 2°, and even 3° alcohols without the need for stoichiometric hydrochloric acid scavengers. The stereoretentive mechanism is probed with a silicon‐stereogenic silane.

     

Cooperative Molecular Motion within a Self‐Assembled Liquid‐Crystalline Molecular Wire: The Case of a TEG‐Substituted Perylenediimide Disc

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).

     

A novel one‐pot oxidative deformylation of N‐formyldihydroquinolines employing ferric chloride hexahydrate. Synthesis of 4‐chloro‐2‐phenylquinolines and 4‐chloro‐2‐(1,3‐diphenyl‐1H‐pyrazol‐4‐yl)quinolines

A novel versatile one‐pot oxidative deformylation approach has been developed to synthesize 4‐chloro‐2‐phenylquinolines and 4‐chloro‐2‐(1,3‐diphenyl‐1H‐pyrazol‐4‐yl)quinolines from the corresponding N‐formyldihydroquinolines.     

M. T. Reetz

“My favorite subject at school was tennis. When I was eighteen I wanted to be a chemist…?.!” This and more about Manfred T. Reetz can be found on page 3731.

     

Total Synthesis of Ouabagenin and Ouabain

All done! A full account of the total synthesis of ouabagenin and ouabain has been described. The synthesis was achieved through a polyanionic cyclization strategy. Degradation studies provide an ultimate proof for a key intermediate observed in the synthesis.

     

Catalytic Hydroaminoalkylation

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).

     

Synthetic Lectins

Improving on Mother Nature? The carbohydrate recognition demonstrated by supramolecular systems in water can now compete with that of natural systems, both in terms of affinity and selectivity. A synthetic carbohydrate receptor displays similar affinity for N‐acetyl‐D ‐glucosamine derivatives as the lectin wheat germ agglutinin and even greater selectivity (see picture: gray C, white H, blue N, red O).

     

Total Synthesis of Ciguatoxin

Eines der Haupttoxine bei Fischvergiftungen, das Ciguatoxin (siehe Struktur), war Ziel einer Totalsynthese. Der Syntheseweg beruht auf der Kupplung dreier Segmente, und die Schlüsselumwandlungen umfassen eine Komplexbildung zwischen Acetylen und Dicobalthexacarbonyl.

     

Oxindole Synthesis by Direct Coupling of C?H and C?H Centers

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).

     

Higher Structure of Cereulide,an Emetic Toxin from Bacillus cereus,and Special Comparison with Valinomycin,an Antibiotic from Streptomyces fulvissimus

Not to be confused : Cereulide is an emetic toxin produced by Bacillus cereus through an unusual non‐ribosomal peptide synthesis, whereas valinomycin, produced by Streptomyces fulvissimus, is a known antibiotic drug. Cereulide has a greater complexation ability with metal ions than valinomycin and also exhibits a K⁺‐ion‐selective ionophore property at lower concentrations than valinomycin.