3D Boranil Complexes with Aggregation-Amplified Circularly Polarized Luminescence.

The development of small organic CPL-active molecules with large luminescent dissymmetry factors is highly demanded due to their promising applications in chiroptical devices and sensors. This work describes the design and synthesis of a new family of CPL-active BF2 complexes, (Rp)/(Sp)-3a-3e, which were constructed by fusing a N̂O-chelated BF2 complex with [2.2]paracyclophane. These complexes display aggregation-amplified CPL with moderate dissymmetry factors values and moderate quantum yields both in solution and in the solid state. In addition, these photophysical properties were rationalized via X-ray diffraction and TD-DFT calculations.

Progress in copper-catalyzed trifluoromethylation.

The introduction of trifluoromethyl groups into organic molecules has attracted great attention in the past five years. In this review, we describe the recent efforts in the development of trifluoromethylation via copper catalysis using nucleophilic, electrophilic or radical trifluoromethylation reagents.

Metal-free enantioselective addition of nucleophilic silicon to aromatic aldehydes catalyzed by a [2.2]paracyclophane-based N-heterocyclic carbene catalyst.

The first example of transition metal-free enantioselective 1,2-silylation of aromatic aldehydes is reported. This protocol enables an easy access to chiral α-hydroxysilanes from readily available aromatic aldehydes.

Application of Bidentate Oxazoline-Carbene Ligands with Planar and Central Chirality in Asymmetric ß-Boration of α,ß-Unsaturated Esters.

A series of new oxazoline-substituted imidazolium salts based on [2.2]paracyclophane were synthesized and characterized. The new bidentate oxazoline-carbene precursor with planar and central chirality had significant advantage than the bicyclic 1,2,4-triazolium salt derived from [2.2]paracyclophane as a monodentate carbene ligand in Cu(I)-catalyzed asymmetric ß-boration of α,ß-unsaturated esters, giving the desired products in high enantioselectivities and yields.

Synthesis and application of a dual chiral [2.2]paracyclophane-based N-heterocyclic carbene in enantioselective ß-boration of acyclic enones.

An enantioselective conjugate addition of boron to α,ß-unsaturated ketones catalysed by either a N-heterocyclic carbene or a copper-carbene complex generated in situ from a new chiral bicyclic triazolium based on [2.2]paracyclophane is presented. The dual chiral carbene-copper catalyst has significant advantages over its carbene counterpart as an organocatalyst in asymmetric ß-boration of acyclic enones, giving a variety of chiral ß-boryl ketones in good yields and enantioselectivities. This is a successful example of employing the same N-heterocyclic carbene in one catalytic reaction as both an organocatalyst and a ligand for transition metal catalysis.

Enantioselective ß-boration of acyclic enones by a [2.2]paracyclophane-based N-heterocyclic carbene copper(I) catalyst.

A new planar and centrally chiral bicyclic 1,2,4-triazolium salt has been synthesized from [2.2]paracyclophane and phenylglycinol. The N-heterocyclic carbene (NHC) copper(I) complex generated in situ by the reaction of the triazolium salt and Cu(2)O was an efficient catalyst for the asymmetric ß-boration of acyclic enones, producing ß-boryl ketones in high yields and enantioselectivities.

5-Benzoyl-13-bromo-4-hy-droxy[2.2]paracyclo-phane.

The title compound, C(23)H(19)BrO(2), was synthesized from 13-bromo-4-hy-droxy[2.2]paracyclo-phane and benzoyl chloride. The hy-droxy and carbonyl groups are involved in intra-molecular O-H⋯O hydrogen bonding. The crystal packing exhibits weak C-H⋯O inter-actions, which link the mol-ecules into sheets parallel to the bc plane.

Synthesis of cyclophanes with planar and helical chirality.

Novel helical macrocyclic imines derived from planar chiral [2.2]paracyclophane were synthesized. The chiroptical properties of the enantiopure compounds were investigated and their absolute configurations were assigned.

Synthesis of a quinazoline derivative: a new α1-adrenoceptor ligand for conjugation to quantum dots to study α1-adrenoceptors in living cells.

Quantum dots (QDs) that are conjugated to small molecule derivatives of drugs and endogenous ligands may be useful tools to study the distribution and dynamic of membrane bound receptors, ion channels and transporters in live cells. In order to use these tools, it is necessary to functionalize QDs with bioactive ligands. In this paper, we successfully synthesized a ligand of α(1)-adrenoceptor that could be conjugated to QDs. In addition, the conjugation of the ligands to QDs and their biological activity were evaluated through binding assay with 30 nM QD conjugates in living human embryonic kidney 293 cells.

12,12'-[2,2'-Oxybis(ethane-2,1-di-yl)bis-(-oxy)]bis-[(R(p))-4-bromo-[2.2]paracyclo-phane].

The title compound, C(36)H(36)Br(2)O(3), was synthesized from (R(p))-4-bromo-12-hy-droxy[2.2]paracyclo-phane and oxydiethane-2,1-diyl bis-(4-methyl-benzene-sulfonate). The crystal packing exhibits a short O⋯Br inter-action [Br⋯O = 3.185 (3) Å] and a weak inter-molecular C-H⋯O contact.

Silylative aromatization of p-quinone methides under metal and solvent free conditions.

A base-mediated silylation reaction leading to benzyl silanes has been developed. Under transition-metal and solvent free conditions, the silylation of a wide array of p-quinone methides is achieved using a Cs2CO3 catalyst in yields up to 96%. Carboxylation of the as-obtained organosilane with gaseous CO2 provides a new synthetic protocol for the preparation of carboxylic acid.

2-Methyl-benzimidazolium nitrate.

In the title compound, C(8)H(9)N(2) (+)·NO(3) (-), inter-molecular N-H⋯O hydrogen bonds join the mol-ecules into a chain extending along the b axis.

An efficient catalyst system for Pd-catalyzed amination of [2.2]paracyclophanyl bromides.

A practical Buchwald-Hartwig amination of [2.2]paracyclophanyl bromides with benzhydrylideneamine is developed. The method provides a facile route to a variety of imino and amino [2.2]paracyclophanes that are otherwise not readily synthesized.

Synthesis and multidrug resistance reversal activity of dihydroptychantol A and its novel derivatives.

The macrocyclic bisbibenzyl dihydroptychantol A (DHA), previously isolated from Asterella angusta, was synthesized and showed significant multidrug resistance (MDR) reverting activity in chemoresistant cancer cells. In an attempt to discover more potent MDR reversal agents for efficient cancer chemotherapy, DHA derivatives with thiazole rings (19-22) were synthesized, and their cytotoxicities and MDR reversal activities were evaluated in adriamycin-resistant K562/A02, vincristine-resistant KB/VCR and in their parental cells by MTT assays. In response to treatment with each compound, the K562 cell line was the most sensitive, and the vincristine-resistant KB/VCR cell line was the most resistant. Marked decreases in K562 and K562/A02 cell viability were detectable after treatment with the synthesized derivatives of DHA, while less inhibitory effects on cell growth were observed in chemical-resistant KB/VCR and KB cells. Moreover, among the tested compounds, the intermediate 17 and the analogues 19, 20, and 21 showed potent MDR reversal activities and increased vincristine cytotoxicity in KB/VCR cells, with the reversal fold ranges from 10.54 to 13.81 (10microM), which is 3.2-4.3-fold stronger than the natural product DHA.

Bis(2,2'-bipyridyl-κN,N')(nitrato-κO,O')(trifluoro-acetato-κO)cadmium(II).

In the title complex, [Cd(C(2)F(3)O(2))(NO(3))(C(10)H(8)N(2))(2)], the Cd(II) ion is hepta-coordinated by two chelating 2,2'-bipyridyl ligands [Cd⋯N 2.370 (6)-2.416 (6) Å], one carboxyl-ate O atom [Cd⋯O 2.290 (6) Å] from the trifluoro-acetate ligand and two O atoms [Cd⋯O 2.386 (6), 2.633 (6) Å] from a chelating nitrate anion. The trifluoro-methyl fragment is rotationally disordered between two orientations in a 0.640 (7):0.360 (7) ratio. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds contribute to the crystal packing stability.

Catalytic enantioselective oxidative coupling of saturated ethers with carboxylic acid derivatives.

Catalytic enantioselective C-C bond forming process through cross-dehydrogenative coupling represents a promising synthetic strategy, but it remains a long-standing challenge in chemistry. Here, we report a formal catalytic enantioselective cross-dehydrogenative coupling of saturated ethers with diverse carboxylic acid derivatives involving an initial oxidative acetal formation, followed by nickel(II)-catalyzed asymmetric alkylation. The one-pot, general, and modular method exhibits wide compatibility of a broad range of saturated ethers not only including prevalent tetrahydrofuran and tetrahydropyran, but also including medium- and large-sized cyclic moieties and acyclic ones with excellent enantioselectivity and functional group tolerance. The application in the rapid preparation of biologically active molecules that are difficult to access with existing methods is also demonstrated.

4-Amino-13-(1-naphth-yl)-[2,2]paracyclo-phane.

THE TITLE COMPOUND [SYSTEMATIC NAME: 1(2)-amino-4(2)-(1-naphth-yl)-1,4(1,4)-dibenzenacyclo-hexa-phane], C(26)H(23)N, was synthesized from 4-amino-13-bromo-[2,2]paracyclo-phane and 1-naphthalene-boronic acid in the presence of 1,4-dioxane. It is a new cyclo-phane-derived compound which can be regarded as a prospective ligand for asymmetric synthesis and catalysis. The benzene rings of the paracyclo-phane units are very slightly deformed from planarity as shallow boats.

Cu-Catalyzed Electrophilic Disulfur Transfer: Synthesis of Unsymmetrical Disulfides.

An efficient electrophilic persulfuration reaction leading to unsymmetrical disulfides and polysulfides has been developed. Various nucleophiles, including aryl boronic acids, ß-keto esters, and thiols, can be used as substrates. The notable features of this method include very simple and practical conditions, general scope, and inexpensive copper catalysts.

Copper(I)-Catalyzed Three-Component Click/Persulfuration Cascade: Regioselective Synthesis of Triazole Disulfides.

A copper(I)-catalyzed three-component CuAAC/persulfuration reaction providing rapid access to asymmetric triazole disulfides has been developed. The interrupted click reaction shows broad substrate scope, complete regioselectivity, and excellent functional group tolerability.

Solid-State Emissive Triarylborane-Based [2.2]Paracyclophanes Displaying Circularly Polarized Luminescence and Thermally Activated Delayed Fluorescence.

New types of [2.2]paracyclophane derivatives, g-BNMe2-Cp and m-BNMe2-Cp, in which electron-donating NMe2 and the electron-accepting BMes2 are introduced at the pseudo -gem and pseudo -meta positions, were designed and synthesized. The efficient through-space charge transfer enables the intense fluorescence with thermally activated delayed fluorescence characteristics. The quantum yields are up to 0.72 and 0.39 in cyclohexane. In addition, no significant fluorescence quenching was observed in the solid state with fluorescence quantum yields of powder up to 0.53 and 0.33. Moreover, the enantiomerically pure forms of g-BNMe2-Cp exhibit strong CPL signals with glum up to 4.24 × 10-3.