Upper Rim-Bridged Calix[4]arenes via Cyclization of Alkynyl Intermediates with Diphenyl Diselenide.

A Sonogashira coupling of -iodocalix[4]arene with various terminal acetylenes confirmed that the position of calixarene is well addressable, and that both thermal and microwave protocols led to good yields of alkynylcalixarenes. Alkynes thus obtained were subjected to the ferric chloride and diphenyl diselenide-promoted electrophilic closure. It turns out that the calix[4]arenes give completely different bridging products than those described for the non-macrocyclic starting compounds.

Chemoselective Electrochemical Cleavage of Sulfonimides as a Direct Way to Sulfonamides.

A new method for selective cleavage of sulfonimides into sulfonamides in high yields using a simple electrochemical approach is shown. As revealed by the electrochemical study, the aromatic sulfonimides can be selectively cleaved by electrolysis of the starting compound at a given potential (only -0.9 V vs SCE for the nosyl group).

Synthesis of Thiapillar[6]arenes Bearing Redox-Active (Hydro)quinone Groups. Electrochemical and XRD Study.

Pillar[]arenes are among the newest members of the macrocyclic family. Nevertheless, their conformational behavior and binding properties as well as redox properties of dealkylated pillar[]arenes are well-studied. At the same time, introducing a heteroatom into a cyclophane macrocycle is already known to alter all the above properties drastically.

Sequence of the supernumerary B chromosome of maize provides insight into its drive mechanism and evolution.

B chromosomes are enigmatic elements in thousands of plant and animal genomes that persist in populations despite being nonessential. They circumvent the laws of Mendelian inheritance but the molecular mechanisms underlying this behavior remain unknown. Here we present the sequence, annotation, and analysis of the maize B chromosome providing insight into its drive mechanism.

Luminescent Cationic Group 4 Metallocene Complexes Stabilized by Pendant N-Donor Groups.

Cationic group 4 metallocene complexes with pendant imine and pyridine donor groups were prepared as stable crystalline [B(CF)] salts either by protonation of the intramolecularly bound ketimide moiety in neutral complexes [(η-CMe){η-CHCMeCMeC(R)═N-κ}MCl] (M = Ti, Zr, Hf; R = -Bu, Ph) by PhNMeH[B(CF)] to give [(η-CMe){η-CHCMeCMeC(R)═NH-κ}MCl][B(CF)] or by chloride ligand abstraction from the complexes [(η-CMe)(η-CHCMeCHCHN)MCl] (M = Ti, Zr) by Li[B(CF)]·2.5EtO to give [(η-CMe)(η-CHCMeCHCHN-κ)MCl][B(CF)]. Solid state structures of the new compounds were established by X-ray diffraction analysis, and their electrochemical behavior was studied by cyclic voltammetry.