Themed collection Chirality

The recent advances of chirality transfer in complexes are described with a special focus on applications in materials science.

This article concentrates on the versatile nucleophilic reactivity of 1,2-dicarbonyl compounds in various asymmetric transformations.

The synthesis of a second-generation [6]-helicenoidal DMAP organocatalyst is reported.

Enantiomorphous adeninium dinitrate crystals acted as the source of chirality in asymmetric autocatalysis to produce (S)- and (R)-alkanols.

The use of a chiral solvating agent (TFPE) for chiral recognition in functionalized metal–organic frameworks by solid-state ¹³C NMR spectroscopy is demonstrated for the first time.

Presented here is the corner-sharing assembly of dodecahedral cavities with both paddle-wheel [M₂(CO₂)₄] units and trimeric [M₃(μ₃-O)(CO₂)₆] units into two isomorphous chiral microporous metal–organic frameworks.

Chiral recognition was affected by helicene stereoisomerism on the surface of gold nanoparticles in their aggregation.

A polythiophene derivative forms chiral aggregates influenced by added sugars, the ICD intensity being correlated with the specific optical rotation.

For the first time, a homochiral MOF membrane was prepared for the enantioselective separation of important chiral compounds.

The first catalytic asymmetric hetero-Diels–Alder reaction between 2-aza-3-silyloxy-1,3-butadienes and aldehydes is described. With Rh₂(S-BPTPI)₄, the cycloaddition reaction gave all-cis-substituted 1,3-oxazinan-4-ones in high yields with up to 98% ee.

The synthesis of a novel class of organosiloxane oligopodes, based on an axially chiral binaphthalene core is described and their mesogenic properties are fully characterised.

We have synthesized a new pair of porous chiral MOFs that were constructed from the same catalytically active bridging ligand but possessed different open channel sizes as a result of the different catenation modes.

Pendant rotaxane switch-tethering poly(m-phenylene diethynylene) was synthesized by polyoxidative coupling of a rotaxane containing an axle-terminal m-diethynylbenzene group and an optically active crown ether. The reversible helix–random coil transition of the polymer was successfully performed by the positional switching of the rotaxane wheel.

Left-handed helical nanofibers were produced from the self-assembly of nucleotide-appended bola-shape molecules in lemon juice.

The emerging and chiroptical switching during the mirror-symmetry-breaking aggregation of optically inactive polysilanes due to solvent limonene chirality were found.

Monitoring racemization allows us to assess helix stability, which is highest in protic solvents.

Rigidly bridged BINAP/biphenylene co-condensed periodic mesoporous organosilica was synthesized and showed crystal-like wall structure and high activity in enantioselective hydrogenations.

Crystal specimens of the γ-polymorph of achiral glycine which crystallize in space groups P3₁ and P3₂ as determined by the anomalous X-ray scattering method are shown to be laevorotatory and dextrorotatory, respectively, as determined by optical rotation of the crystals.

An intelligent chiral chemosensor capable of chirality amplification was designed and constructed as poly(phenyleneethynylene) having chiral pseudo-18-crown-6. Both sensitivity and selectivity were amplified from those limited by the law of mass action.

We propose that there is a vast ocean of chiral crystals just waiting to be discovered/proclaimed.

Chiral benzylic amines were obtained through the Friedel–Crafts reactions between phenols and N-tosylaldimines catalyzed by a leucine-derived catalyst.

Asymmetric aldol reactions take place via axially chiral enolate intermediates to give chiral oxazolidones with a tetrasubstituted chiral center.

The kinetics of growth for chiral J-aggregates of H₄TPPS₄ porphyrin have been investigated under different experimental conditions in the presence of tartaric acid. The observed rate constants and the anisotropy factor g show a defined dependence on the enantiomer used as a chiral templating agent.

A new chiral tetraphenylethylene derivative with the AIE effect was synthesized and showed not only high enantioselectivity for a wide range of chiral acids but also a high sensitivity of 10⁻⁶ M scale. The enantiomeric purity of chiral acids could be quantitatively determined by this chiral sensor.

Chiral separation of cyclic triamide 4a was achieved by simple crystallization to afford chiral capsule-type dimer structure.

Pseudo helix-sense-selective polymerization of achiral substituted acetylenes having dynamic covalent bonds to yield static one-handed helical polymers has been achieved.

Humidity sensing by hydrolysis of a chiral dopant in a cholesteric liquid crystal leading to irreversible color change is demonstrated.

Camphorthiolate-protected Au₂₅ clusters were synthesised. The optical activity is traced to the chirality of the ligands and is dominated by their orientation rather than their internal structure.

A variety of different chiral forms, including unprecedented croissants, are self-assembled from helical supramolecular fibres by varying the processing conditions.

A small chemical structure change causes a remarkable influence on the stereomutational rate of helical vinyl glycopolymers.

Two strategies for the syntheses of chiral porphyrin–(bis)calixarene multi-component supramolecular assemblies are reported.

Main-chain polymers of chiral imidazolidinone are useful as polymeric chiral organocatalysts for the asymmetric Diels–Alder reaction of cyclopentadiene and cinnamaldehyde.

A new synthetic route to chiral γ- and δ-lactones has been demonstrated via asymmetric allylic carboxylation with a planar-chiral Cp′Ru catalyst and RCM.

Coiled fibrils are preferably formed by perfluorinated gelators when an optical antipode is added to the surplus amount of chiral aggregates, while crystals are formed immediately from the pure enantiomer form.

The structure of the alkane solvent strongly affects the expression of the supramolecular chirality in stereoselectively deuterated benzene-1,3,5-tricarboxamides.

A diastereomer pair of left- and right-handed square planar Pd(II) complexes was synthesized from a single chiral ligand as kinetic and thermodynamic products. Helicity inversion between the diastereomers occurred rapidly under thermal and microwave irradiation conditions.

A simple one-pot transformation from tosylaldimines towards chiral 1,2-amino alcohols by enantioselective metal free boryl addition to CN followed by homologation/oxidation.

A helical phase is formed in the blends of chiral block copolymer due to an enhancement of helical steric hindrance.

Enantioenrichment in two-component amino acid mixtures is obtained after sublimation, provided that one converts into a conglomerate phase.

Calculated ee values of the peptide chains of each chain length l for three starting concentrations (in moles) of the host and guest monomers r_tot : r′_tot : s_tot : s′_tot.

DKR of racemic secondary alcohols was achieved efficiently by the combined catalyst system of bifunctional amidoiridium complexes with CALB.

A dinuclear double helical complex [Ag₂L₂]²⁺ assembles into infinite chains via Ag⋯Ag interactions; three such chains form a triple helical braid in the crystal which therefore displays three distinct levels of supramolecular organisation.

meta-Ethynylpyridine 18-mer associates with octyl β-D-glucopyranoside to show an induced circular dichroism (ICD) band around 337 nm in CH₂Cl₂. The ICD was enhanced and memorized by the addition of copper(II) triflate and o-phenanthroline.

Helical polymer brushes bearing a polyacetylene backbone and polyisocyanate pendants were synthesized, whose helix-sense was controlled by the chiral domino effect.

An achiral polythiophene formed a unique optically active metal-induced supramolecular aggregate upon complexation with chiral amines or in the presence of a chiral polythiophene in a good solvent for the polymers, thus showing an induced circular dichroism.

A series of oligoparaxylenes with multiple axes of chirality was synthesized and their atropisomers were found by variable temperature ¹H NMR spectroscopy to obey the Losanitsch series.

The interconverting stereoisomers of tri-o-thymotide have been separated by HPLC on chiral stationary phases and the dynamic chromatographic patterns interpreted in terms of exchange between enantiomeric helical and propeller conformations.

From two initial ILs two other ILs are obtained by simultaneous ion exchange giving access to an eco-friendly ELLE process.

A new bifunctional C-5′ substituted cinchona alkaloid-based catalyst promotes the first highly enantioselective additions of alkyl thiols to nitrostyrenes.

Nearly racemic ketoprofen was spontaneously resolved into the two enantiomers by simple crystallization under nonequilibrium preferential enrichment conditions.

Indium-mediated allylation of N-tert-butanesulfinyl ketimines afforded in high yields and diastereoselectivities homoallylic amine derivatives with the nitrogen atom bonded to a quaternary stereocenter.

The tandem Crabbé homologation-radical rearrangement of terminal enediynes leads, in a one-pot procedure, to the enantioselective synthesis of six- and seven-membered ring α-aminoesters bearing a quaternary stereocenter based on the phenomenon of memory of chirality.

The enantiomeric outcome of DNA-based catalytic reactions is controlled by the denticity of the ligand coordinated to the Cu(II) ion.

The first Lewis base-catalysed asymmetric assembly of α-angelica lactone and Morita–Baylis–Hillman carbonates of isatins has been developed.

A supramolecular growth process based on secondary nucleation controls the chiral amplification of a lock-washer shaped foldamer.

A new strategy is established for detecting chiral amino acids based on the electron transfer from hemoglobin Fe(II) to Cu(II) in copper complexes of the amino acids.

Robust chiral gels were obtained from alkane solutions with rationally designed nickel–bis(dithiolene) complexes appended with cholesteryl fragments.

A highly enantioselective catalytic Mukaiyama aldol reaction of silyl enol ethers with aldehydes in aqueous conditions is described using a chiral Fe^II–bipyridine complex.

A universal method to determine handedness of 2₁ helical assemblies composed of planar aromatic molecules is proposed.

A variety of 2-amido pyrrolidines, including Weinreb-type amides, have been prepared with very high exo diastereoselectivity and enantioselectivitiy in the reaction of α-iminoamides with activated alkenes.

A preferred-handed helical conformation was reversibly induced to poly(9,9-dioctylfluoren-2,7-diyl) upon irradiation by circularly polarized light as the only source of chirality.