Control of chemoselectivity is one of the most challenging problems facing chemists and is particularly important in the synthesis of bioactive compounds and medications. Herein, the first highly chemoselective tandem C(sp3)-H arylation/[1,2]-Wittig rearrangement of pyridylmethyl ethers is presented. The efficient and operationally simple protocols enable generation of either arylation products...

Host–guest chemistry encompasses the study of highly structured molecular complexes composed of at least two entities associated by noncovalent interactions, one possessing convergent binding sites, the host, and another possessing divergent binding sites, the guest. Among other species, the host can be a crown ether, calixarene, or metallacycle, whereas the guest can be virtually any small-tom...

Lithiation and subsequent reaction with CO(2) was applied to calix[4]arenes with different, equal or mixed, ether functions at the lower-rim site as well as tert-butylated or non-tert-butylated upper-rim positions. Whereas this reaction fails for symmetric calix[4]arene ethers with alkoxy residues greater than methoxy, the carboxylation of mixed methoxy-propoxy calixarene ethers is possible. In...

An AB2 monomer containing a bis(m-phenylene)-32-crown-10 and two paraquat moieties was designed and prepared. It self-organized to form a supramolecular hyperbranched polymer in solution.

In the title compound, C(6)H(5)Cl(3)N(+)·ClO(4) (-)·C(12)H(24)O(6), the perchlorate anion is disordered over two orientations in a 0.666 (17):0.334 (17) ratio. The ammonium group of the organic cation inserts into the crown ether ring and forms three bifurcated N-H⋯(O,O) hydrogen bonds to generate a supra-molecular complex. The macrocycle has approximate D(3d) local symmetry.

Pseudorotaxanes from self-assembly of two crown ether-based cryptand wheels and a 1,2-bis(pyridinium) ethane derivative axle were prepared.

In the title compound, 2CH(6)N(3) (+)·2Br(-)·C(12)H(24)O(6), the 18-crown-6 mol-ecule lies about an inversion center, whereas the guanidinium cation and bromide anion are in general positions. The guanidinium cations link with the bromide anions and the crown ether mol-ecules via N-H⋯O and N-H⋯Br hydrogen bonds, thus forming a three-dimensional network.

A benign and efficient synthesis of chiral macrocyclic 'aza-crown' ethers of varying ring size is reported. The synthesis involves a Schiff base condensation of ether linked dialdehydes of varying chain length and (1R,2R)-(-)-1,2-diaminocyclohexane under mild conditions to yield the macrocycles, which are subsequently reduced to yield the diamino analogues.

The construction of novel mechanically interlocked structures has become a topic of great current interest due to the requirements of topology and their potential application in molecular machines and devices. Rotaxane and catenane as two basic topological frameworks can be used to construct the fused structures. In the current investigation, a class of novel ammonium backbones were synthesized...

The high valent molybdenum-dioxo complex [MoO2Cl2] catalyzes the addition of dimethylphenylsilane to aldehydes and ketones to afford the corresponding dimethylphenylsilyl ethers in quantitative yield.