Synthesis of Azo-Substituted Bicyclo[1.1.1]pentanes (BCPs) via Base-Promoted Halogen Atom Transfer.

Because of the three-dimensional bioisosteric feature, bicyclo[1.1.1]pentylamines (BCPAs) are valuable scaffolds in synthetic chemistry and medicinal chemistry.

A 12-Vertex Metallacarborane of Silver(I).

The discovery of ferrocene in 1951 was a significant landmark in the field of organometallic chemistry, and since then, numerous sandwich- or half-sandwich metallic complexes have been reported. However, silver stands as an intriguing exception in this regard, and knowledge of its bonding situation has remained undisclosed. Herein, unprecedented 12-vertex metallacarboranes of Ag(I) ( and ) were synthesized through the reaction of sodium hexamethyldisilazide (NaHMDS) with the mixture of -CB carborane anion-supported -heterocyclic carbene precursors ( and ) and [Ag(PPh)Cl].

Benzyl Deuteriodifluoromethyl Sulfoxide: An Easily Accessible and Stable Reagent for Direct Deuterodifluoromethylthiolation.

A new, stable and scalable reagent based on a sulfoxide skeleton for direct deuteriodifluoromethylthiolation has been developed. The reagent displays excellent reactivities toward TfO promoted C-H deuteriodifluoromethylthiolation of electron-rich arenes, indoles, alkenes, and intramolecular lactonization of 2-alkynylbenzoates. Moreover, high deuteration rates and good to excellent yields were achieved under metal-free reaction conditions.

Nickelacarborane-Supported Bis--heterocyclic Carbenes.

Metallacarboranes have attracted significant attention due to their unique properties. Considerable efforts have been made on the reactions around the metal centers or the metal ion itself, while transformations of functional groups of the metallacarboranes have been much less explored. We presented here the formation of imidazolium-functionalized nickelacarboranes (), their subsequent conversion to nickelacarborane-supported -heterocyclic carbenoids (NHCs, ), and the reactivities of toward Au(PPh)Cl and Se powder, which resulted in the formation of bis-gold carbene complexes () and NHC selenium adducts ().

Cyclic Carbonate Synthesis from Epoxides and CO Catalyzed by Aluminum-Salen Complexes Bearing a -CB Carborane Ligand.

The active and well-designed Schiff base ligands are considered "privileged ligands". The so-called salen ligands, i.e.

Employing Visible-Light Photoredox Catalysis in Multicomponent-Multicatalyst Reactions: One-Pot Synthesis of Spiroquinazolin-2-(thi)ones.

The multicomponent-multicatalyst reaction ((MC)R) and visible-light catalysis have emerged as green and powerful strategies for achieving ideal syntheses. Here, we report the first example of a visible-light-induced approach toward spiroquinazolin(thi)ones. This (MC)R features an eco-friendly energy source and solvent, metal-free catalysts, step- and atom-economy, a relay catalysis strategy, air as green oxidant, mild conditions, and easily accessible starting materials.

Environmentally Benign Synthesis of Quinoline-Spiroquinazolinones by Iron-Catalyzed Dehydrogenative [4 + 2] Cycloaddition of Secondary/Tertiary Anilines and 4-Methylene-quinazolinones.

We report an efficient iron-catalyzed cross-dehydrogenative coupling [4 + 2] annulation of secondary/tertiary anilines with quinazolinones to generate quinoline-spiroquinzolinones. The reaction proceeds smoothly with a relatively broad variety of functional groups, a cheap transition metal catalyst (FeCl), and environmentally friendly oxidant (HO/O) under mild reaction conditions. Creatively, -methylanilines are employed for the first time for the cycloaddition as both methyl and methylene sources attached to the N atom of tetrahydroquinolines.

DMSO as a Dual Carbon Synthon and Water as Oxygen Donor for the Construction of 1,3,5-Oxadiazines from Amidines.

A selective and efficient synthesis of diaryl 1,3,5-oxadiazines was established for the first time from simple and readily available amidines in wet DMSO. DMSO was employed as a dual carbon synthon and water offered the oxygen atom to construct the oxadiazine ring. The reaction involved two new C-N and two new C-O bond formations.

Sustainable Four-Component Annulation for the Synthesis of 2,3,4,6-Tetraarylpyridines.

A one-pot, four-component annulation of 2,3,4,6-tetraarylpyridines from aromatic aldehydes, methyl ketones, diaryl ethanones, and ammonium acetate is described. The reaction features high functional group compatibility in air under solvent-free conditions without any additive and only water as the nontoxic byproduct, providing a strategy for the facile, economical, and eco-friendly construction of multiaryl-substituted pyridines from simple and readily available reactants.

Expeditious Approach to Indoloquinazolinones via Double Annulations of -Aminoacetophenones and Isocyanates.

A novel procedure for a one-pot cascade reaction of -aminoacetophenones and aryl/aliphatic isocyanates catalyzed/oxidized by the [Pd]/[Ag] system was developed. The reaction involves two C-N bond and one C-C bond formations during the double annulation process and the desired indoloquinazolinones and derivatives were afforded up to 81% yields from readily available substrates with a tolerance of a broad variety.

Catalytic Asymmetric trans-Selective Hydrosilylation of Bisalkynes to Access AIE and CPL-Active Silicon-Stereogenic Benzosiloles.

Chirality widely exists in a diverse array of biologically active molecules and life forms, and the catalytic constructions of chiral molecules have triggered a heightened interest in the fields of chemistry and materials and pharmaceutical sciences. However, the synthesis of silicon-stereogenic organosilicon compounds is generally recognized as a much more difficult task than that of carbon-stereogenic centers because of no abundant organosilicon-based chiral sources in nature. Herein, we reported a highly enantioselective rhodium-catalyzed trans-selective hydrosilylation of silicon-tethered bisalkynes to access chiral benzosiloles bearing a silicon-stereogenic center.

A Stable Cyclic (R SnAu) Anion Having In-Plane σ-Möbius Aromaticity.

A cyclic (R SnAu) anion (3 , R Sn=2,2,5,5-tetrakis(trimethylsilyl)-1-stannacyclopentane-1,1-diyl) has been synthesized as a stable blue salt with K (THF) through the reaction of stable dialkylstannylene 1 with R' PAuCl (R'=Et, Ph) followed by the reduction with KC . Crystallographic and NMR analysis shows that the six-membered (SnAu) ring of 3 is planar and highly symmetric with an equal distance of six Au-Sn bonds. A UV/Vis spectrum of 3 in hexane reveals an intense absorption maximum at 598 nm.

A Simple Metal-Free Cyclization for the Synthesis of 4-Methylene-3-Substituted Quinazolinone and Quinazolinthione Derivatives: Experiment and Theory.

A new series of 3-substituted 4-methylene-quinazolinthiones and 4-methylene-quinazolinones were synthesized in moderate to excellent yield through a simple reaction of 2-aminoacetophenones with isocyanates or isothiocyanates. The reaction shows good tolerance of many important functional groups in the presence of air and water under metal-free conditions. Only water is produced as a coproduct, rendering this "green" methodology a highly versatile and eco-friendly alternative to the existing methods for the construction of the quinazolinone/quinazolinthione framework.

Synthesis, structure and DFT calculations of 1,2-N-substituted o-carboranes.

A series of 1,2-N-substituted o-carboranes were obtained. The C-C bond lengths of secondary-amino o-carboranes 3 were compared. The relationship between C-C distances and the electron effects of the benzyl groups was discussed.

Exceptionally Long C-C Single Bonds in Diamino-o-carborane as Induced by Negative Hyperconjugation.

The synthesis of a series of 1,2-diamino-o-carboranes (1-4) is reported. The molecular structures of these diamino-o-carboranes are remarkable as the inner-cluster C-C bonds are all ultra-long (162.7-193.

Disilanylene-bridged BODIPY-based D-σ-A architectures: a novel promising series of NLO chromophores.

The synthesis and optical properties of a novel series of disilanylene-bridged BODIPY-based D-σ-A chromophores are reported. Si-Si σ-electrons are useful and impressible for tunable optical properties. The electron-donating group facilitates enhancement of the CT nature of the excited state through σ(Si-Si) orbital, leading to the remarkable two-photon absorption cross-sections.

Cation-Triggered Stannate(II)/Stannylenoid/Stannylene Conversion.

The reaction of dipotassio-tetrasilan-1,4-diide (4) with anhydrous SnCl at low temperature results in the formation of a five-membered cyclic potassio chlorostannate(II) ([(18-C-6)K](1)). By careful cation exchange reactions, it was transformed into the sodium chlorostannylenoid 2 (by using Na [B Cl ]) or into the non-stabilized cyclic bissilylstannylene 3 (through applying Li[Al(OC(CF ) ) ]). The increasing Lewis basicity of the bissilylstannylene 3 was analyzed by combined methods of DFT calculations and NMR spectroscopy and substantiated by the synthesis of the corresponding iron carbonyl complexes 7 and 8 from the chlorostannate 1 and the stannylene 3, respectively.

N-Bridged Annulated BODIPYs: Synthesis of Highly Fluorescent Blueshifted Dyes.

A series of novel BODIPY dyes has been prepared through the introduction of an N-bridged annulated meso-phenyl ring at one of the β-positions of the BODIPY core. An unusual blueshift of the main spectral bands is observed, since the fusion of a meso-substituent results in a marked relative destabilization of the LUMO. The greater rigidity of the ring-fused structure leads to very high fluorescence quantum yields.

Silyl- and Disilanyl-BODIPYs: Synthesis via Catalytic Dehalosilylation and Spectroscopic Properties.

We describe herein the first synthesis of silyl- and disilanyl-BODIPYs through transition-metal-catalyzed dehalosilylation of iodo-BODIPYs using a Pd(P(tBu) ) /Et N/toluene system. Various mono- and bis-silyl-BODIPYs, mono- and bis-disilanyl-BODIPYs and bis-BODIPYs linked by silylene and SiOSi groups were synthesized by using this straightforward method. Silyl- and disilanyl-substitution significantly modifies the spectroscopic properties of the BODIPY, in which the fluorescence quantum yields of the silyl-BODIPYs are remarkably increased, whereas the emission spectra of disilanyl-BODIPYs are red-shifted due to effective σ(SiSi)-π(BODIPY) conjugation.

Reversible Stannylenoid Formation from the Corresponding Stannylene and Cesium Fluoride.

A fluorostannylenoid (Cs [R SnF] (9), R =(TMS) CCH CH C(TMS) ) was prepared by reacting a stable dialkylstannylene (R Sn (8), R =(TMS) CCH CH C(TMS) ) with cesium fluoride at room temperature in THF. While 9 is stable in THF and DME, removal of the solvent leads to the regeneration of stannylene 8. No reaction occurred when 8 was treated with CsF in a hydrocarbon solvent.

Reactions of an Isolable Dialkylsilylene with Aroyl Chlorides. A New Route to Aroylsilanes.

The reactions of isolable dialkylsilylene with aromatic acyl chlorides afforded aroylsilanes - exclusively. Aroylsilanes - were characterized by ¹H-, C-, and Si-NMR spectroscopy, high-resolution mass spectrometry (HRMS), and single-crystal molecular structure analysis. The reaction mechanisms are discussed in comparison with related reaction of with chloroalkanes and chlorosilanes.

A Chiral Hemiporphyrazine Derivative: Synthesis and Chiroptical Properties.

The synthesis of an optically active hemiporphyrazine with chiral binaphthyl substituents (1) is reported, providing the first example of the incorporation of an intrinsically chiral moiety into the macrocyclic core of a hemiporphyrazine analogue. A negative circular dichroism (CD) signal is observed in the 325-450 nm region of the CD spectrum of (S,S)-1, while mainly positive bands are observed in the 220-325 nm region. Mirror symmetry is observed across the entire wavelength range of the CD spectra of (R,R)-1 and (S,S)-1.

1,3-Diazasilabicyclo[1.1.0]butane with a Long Bridging N-N Bond.

A 1,3-diazasilabicyclo[1.1.0]butane (1) is synthesized as thermally stable crystals by using the cycloaddition reaction of an isolable dialkylsilylene with aziadamantane.