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A ligand-free Cu-catalyzed [3 + 2] cycloaddition of ethyl 2-(quinolin-2-yl)acetates, ethyl 2-(isoquinolin-1-yl)acetates, and ethyl 2-(pyridin-2-yl)acetates with (E)-chalcones for a “one-pot” synthesis of pyrrolo[1,2-a]quinolines, pyrrolo[2,1-a]isoquinolines and indolizines has been developed. The annulation products were isolated in moderate to good yields with air as the sole oxidant under mild conditions.

Methods for trifluoromethylthiolation are very limited. To tackle this problem, a mild and efficient approach to the 2-trifluoromethylthiolation of glycals has been developed. This protocol employed N-trifluoromethylthiosaccharin as the trifluoromethylthiolating reagent, TMSCl as the activator, and DBU as the base, affording 2-trifluoromethylthioglycals in good yields. These trifluoromethylthiolated carbohydrates may benefit the development of carbohydrate-based drugs.

An efficient one-pot method for the syntheses of di- and polybrominated esters from readily available aldehydes is reported. The direct use of the in situ generated byproduct PPh3O in the following reactions greatly improves the efficiency of the cascade. Also, the substrate scope of the reaction is proved to be broad.

A metal-free direct α-selective arylation of BODIPYs has been developed based on base-mediated C–H functionalization with easily accessible diaryliodonium salts, which provides a straightforward facile access to a variety of α-arylBODIPY dyes. The α-regioselectivity was confirmed by X-ray analysis, and was studied by DFT calculation. The resultant dyes show strong absorption and emission over a broad range of spectra tunable via the simple variation of the diaryliodonium salts.

A chiral amine catalyzed enantioselective α-functionalization of α-substituted β-ketocarbonyls with electron-deficient vinylarenes has been developed to construct the dicarbonyl products with the formation of a chiral all-carbon quaternary stereocenter. The products can be used for the efficient synthesis of useful but challenging chiral quaternary centered pyrazolones.

The formation of unsaturated carbonyl ylides via rhodium-catalyzed carbene cyclization with enones and their subsequent inter- and intramolecular cycloadditions to construct functionalized oxapolycyclic rings have been realized.

The acylation reaction tolerates aromatic and aliphatic amines and proceeds with high selectivity towards amines over hydroxy functionalities.

The palladium-catalyzed coupling of olefins and organohalides is a versatile approach for synthesizing complex molecules from simple starting materials. We have developed a palladium-catalyzed coupling of α-bromocarbonyl compounds with allylic alcohols for the generation of acyclic aryl-substituted dicarbonyl compounds. The reaction proceeds via a tandem olefin insertion of an α-acyl radical followed by a 1,2-aryl migration. In addition to providing preliminary evidence for a free radical mediated mechanism, we demonstrate unprecedented levels of 1,3-stereoinduction for the 1,2-migration step.

The first direct vinylogous Michael addition of unmodified linear substrates to α,β-unsaturated aldehydes by employing a rationally designed multifunctional supramolecular iminium catalysis strategy is developed.

An efficient manganese(II)/O2-promoted oxidative radical cascade reaction was developed for the modular synthesis of multi-substituted isoquinolines from easily accessible vinyl isocyanides and boronic acids.

Four new acoranes [(I)-(III)], a novel cadinane (IV), and a novel guaiane (V) are isolated together with six known compounds.

Norsampsones A–D (1–4), four new decarbonyl polycyclic polyprenylated acylphloroglucinols, together with a new biogenetically related compound hypersampsone M (5), were isolated from the aerial parts of Hypericum sampsonii. Norsampsones A–D featured an unprecedented carbon skeleton with the loss of C-2 carbonyl in the phloroglucinol ring. All structures were determined by extensive NMR spectroscopic methods, ECD calculation, and single-crystal X-ray diffraction.

The Ph3PO-catalyzed reaction of α,β-unsaturated esters (I) and β,γ-unsaturated α-ketoesters (VII) with oxalyl bromide affords trans-dibromides (II) and (VIII), resp., with good to high diastereoselectivity.

An efficient rhodium-catalyzed regioselective C–N bond formation of azo compounds in good to excellent yields through C–H bond functionalization using azides as the nitrogen source was developed. Alkyl, aryl, and sulfonyl azides could be efficiently assembled in this reaction with excellent functional group tolerance.

The first example of a homogeneous gold-catalyzed rearrangement of propargylic esters followed by hypervalent iodine promoted oxidation is described to allow a new approach to ynones, generally in good to moderate yields.

An unusual Ph3PO-catalyzed stereoselective 1,3-dicholorination of an unsaturated ketoester has been developed. The novel activation mode involved in this cascade reaction can promote consecutively elusive transformations. The products were obtained with good yields and excellent stereoselectivities. This reaction makes important complementation to the limitations associated with the field of dichlorination.

A self-assembled nano-sized Pd6L8 (L = 1,3,5-tris(4′-pyridyloxadiazole)-2,4,6-triethylbenzene) ball was constructed based on a new oxadiazole-containing tripod. In H2O–EtOH mixed-solvent system, Pd(II)-ball displays excellent performance in Suzuki–Miyaura cross-coupling reactions at low catalyst loading under ambient conditions in a homogeneous fashion. Furthermore, it shows heterogeneous catalyst nature in o-xylene and can be reused without loss of catalytic activity.

A Au/Ag-catalyzed phosphatyloxy or carbonate double migration of functionalized amides of type (I) offers a highly diastereoselective synthesis of 3,4-disubstituted butyrolactams.

Desymmetrization of carbon nucleophiles by palladium-catalyzed asymmetric allylic alkylation has been realized for the first time. Products with three chiral centers were obtained in good yield and with high diastereo- and enantioselectivity. The method offers an efficient access to optically active tropane derivatives.

New perspectives, in particular for the synthesis of isochromane derivatives (see scheme), are provided by the title reaction. Excellent diastereoselectivites are achieved in this reaction which proceeds through a gold-catalyzed 1,3-acyloxy migration. In some cases exclusively the Z isomer is detected.

Some readily available Boc-protected 2-(3-methoxy-1-propynyl)anilines and nitrones in platinum-catalyzed reactions deliver [1,2]oxazino[5,4-b]indoles. Twelve examples with yields of 41–95% are reported. Different substituents like nitro, trifluoromethyl, fluoro, bromo, and ester groups are tolerated. With regard to the mechanism, this reaction probably combines an initial intramolecular cyclization/elimination to vinylcarbenoid species and a subsequent stepwise intermolecular [3+3] cycloaddition with the nitrones.

(C10H10N2)12 (PMo12O40)2 (SrP6MoV3MoVI15 O73)2·9H2O is hydrothermally synthesized from a mixture of Na2MoO4, 4,4′-bipyridine, H3PO4, SrCl2, and H2O (pH 3 adjusted with NaOH, 160 °C, autoclave, 4 d; 40% yield).

Title praseodymium complex efficiently catalyzes the cyclotrimerization of aryl isocyanates (I) to give sym-triazines (II) in excellent yields.

The novel layered phosphate (III) crystallizes in the monoclinic space group P21/n with Z = 2 (single crystal XRD).

The new compound (III) crystallizes in the monoclinic space group P21/n with Z = 2 (single crystal XRD).

Two 3D hybrid sandwich-type polyoxometalates, [{l_brace}Sr(H{sub 2}O){sub 5}Sr(H{sub 2}O){sub 6}Sr{sub 0.5}(H{sub 2}O){sub 7{r_brace}2}Mn{sub 4}(H{sub 2}O){sub 2}({alpha}-PW{sub 9}O{sub 34}){sub 2}].6H{sub 2}O (1) and [{l_brace}Sr(H{sub 2}O){sub 6}[Sr(H{sub 2}O){sub 8}]{sub 2}Sr(H{sub 2}O){sub 4{r_brace}2}Mn{sub 4}(H{sub 2}O){sub 2}({alpha}{beta}{beta}{alpha}-P{sub 2}W{sub 15}O{sub 56}){sub 2}].5H{sub 2}O (2), have been obtained by the routine synthetic reactions in aqueous solution and characterized by IR, elemental analysis, thermal analysis, and X-ray single-crystal diffraction. The 3D hybrid framework of 1 and 2 are built by tetra-Mn{sup II} substituted sandwich-type polyoxotungstates modified by fourteen Sr(H{sub 2}O){sub x} (x=4-8) units acting as bridges, forming centrosymmetric sandwich structures. The magnetic property of compound 1 has been studied by measuring its magnetic susceptibility in the temperature range of 2-300 K, which indicates predominant ferromagnetic interactions between the Mn{sup II}-O-Mn{sup II} bridge unit. Additionally, the electrochemical behaviours have been detected on solid bulk modified carbon paste electrodes of compounds (CPEs) and three redox couples are detected. - Graphical abstract: Two compounds based on Keggin(a) and Wells-Dawson(b) polyoxometalates modified by 14 Sr-O clusters.

The bridging nitrones 7, 8 incorporated in a homoadamantane ring system were obtained by oxidation of 4-azahomoadamantane 5, 6 with SeO2/H2O2. The 1,3-dipolar cycloaddition reaction of these nitrones with the electron-deficient alkynes proceeded regiospecifically at 0 °C-r. t. to give 4-substituted isoxazolines. The reaction with phenylacetylene required forced conditions, where 5-substituted isoxazoline 9d was obtained from 7 using the dipolarophile as a solvent, and rearranged pyrrole 12d was formed directly from 8 at a higher reaction temperature. The resulted cycloadducts from ketonitrone 8 were further converted to homoadamantane-fused pyrroles. In this case, 2-substituted and 3-substituted pyrroles 12a and 12e were obtained respectively from the same starting material via the different mechanism. The former arose via an acylaziridine route by thermolysis and the latter via an enamine route in protic solvents.

A practical reactivity of nitrile groups as dipolarophiles in 1,3-dipolar cycloadditions with 4-azahomoadamant-4-ene N-oxides 1 and 2, 2,2-dimethyl-3,4-dihydro-2H-pyrrole N-oxide 8 and N-benzylidenephenylamine N-oxide 10 is reported. Benzonitriles 3c–i reacted with these nitrones upon heating for more than 12 h to afford the corresponding 2,3-dihydro-1,2,4-oxadiazole derivatives. The reaction of acetonitrile 3b with nitrone 1 required a prolonged reaction time (15 days). However, the reaction of an activated nitrile, methyl cyanoformate 3j, proceeded smoothly under milder conditions (25 °C for 1, 2 and 8, and 80 °C for 10).

(1997). SYNTHESIS OF NITRONES FROM 3,4-DIHYDROISOQUINOLINE DERIVATIVES BY OXIDATION WITH m-CHLOROPEROXYBENZOIC ACID. Organic Preparations and Procedures International: Vol. 29, No. 2, pp. 185-194.

The single crystals of perovskite fluorides (NH4)2NaVF6 and Na3VF6 were synthesized under mild hydrothermal conditions. The structures of the compounds were determined by means of single-crystal and powder X-ray diffraction analyses, respectively. (NH4)2NaVF6 has a cubic elpasolite-type structure and crystallizes in the space group Fm 3 ¯ m with lattice constant a=8.495(0) A. Rietveld refinement indicates that Na3VF6 has a monoclinic structure and is in space group P21/n. The compounds were characterized by scanning electron microscopy, thermogravimetric and differential thermal analysis, and variable temperature magnetic susceptibility. With the temperature decreasing, the magnetic studies of the compounds showed the magnetic ordering was related to the crystallographic features and isolated magnetic units.

A new three-dimensional (3D) zincophosphite |Co(en)3| [Zn4(HPO3)5(H2PO3)] (1) has been solvothermally synthesized by using a racemic mixture of a chiral cobaltammine complex Co(en)3Cl3 as the structure-directing agent. Single-crystal X-ray diffraction analysis reveals that compound 1 crystallizes in the monoclinic space group P21/c (no. 14) with a=18.6180 (4) A, b=8.7601(18) A, c=17.4840(4) A, β=93.42(3)°, V=2846.4(10) A3, Z=4 with R1=0.0530. Its structure is built up from strict alternation of ZnO4 tetrahedra and HPO3 pseudo-tetrahedra, giving rise to a 3D inorganic framework with 4-, 6-, 8-, 10- and 12 MRs, and the metal complex molecules, both the Δ and Λ enantiomers, sit in 10-MRs channels. In addition, it is worth noting that left- and right-handed helical chains exist in the framework, which is induced by chiral metal complex Co(en)3Cl3 template molecules. Further characterization of compound 1 has been performed, including X-ray powder diffraction, ICP, CHN, IR and TG analyses.

A search for stress inducing metabolites produced by the plant pathogenic fungus Leptosphaeria maculans led to the isolation and structure elucidation of eight new metabolites, the leptomaculins and deacetylleptomaculins A-E. The chemical structures and absolute stereochemistry of the new metabolites were deduced by detailed analysis of 1D and 2D NMR spectroscopic data and chemical degradation of the toxin sirodesmin PL. Leptomaculins A and B are the first examples of naturally occurring 2,3-oxopiperazinethione and 2,3-dioxopiperazine, respectively. Stress inducing activity was found in the fungal phytotoxins sirodesmin PL and deacetylsirodesmin PL but not in any of the new leptomaculins, phomalide or phomamide. A metabolic pathway for biosynthesis of the first 2,3-(di)oxopiperazine(thione) from sirodesmin PL is proposed.

Dendronobilins K - N, four new sesquiterpenes with copacamphane-type (1), picrotoxane-type (2, 3) and cyclocopacamphane-type (4) skeletons, were isolated from the n-BuOH soluble fraction of the 60% ethanol extract of the stems of Dendrobium nobile. Their structures were established as 2beta,11,12-trihydroxycopacamphan-15-one (1), (2beta,3beta,4beta,5beta)-2,4,11,12-tetrahydroxypicrotoxan-3(15)-olactone (2), (2beta,3beta,5beta)-2,11,12,13-tetrahydroxypicrotoxan-3(15)-olactone (3), and (5beta,8beta)-cyclocopacamphane-5,8,12,15-tetrol (4) on the basis of spectroscopic analysis. Compounds 3 and 4 were inactive in both immunomodulatory and antioxidant bioassay in vitro.

Three new molybdophosphates, [Co(dien){sub 2}].(H{sub 3}dien){sub 6}.{l_brace}[CoMo{sub 12}O{sub 24}(OH){sub 6}(HPO{sub 4}){sub 2}(PO{sub 4}){sub 6}][Co(Hdien)]{sub 2}[CoMo{sub 12}O{sub 24} (OH){sub 6}(PO{sub 4}){sub 8}]{r_brace}.(dien).4H{sub 3}O.5H{sub 2}O (1) (H{sub 3}dien){sub 4}[MMo{sub 12}O{sub 24}(OH){sub 6}(HPO{sub 4}){sub 4}(PO{sub 4}){sub 4}].10H{sub 2}O [M=Co for (2), Ni for (3); dien=diethylenetriamine], have been synthesized by employing hydrothermal method and characterized by single crystal X-ray diffraction. Compound 1 is built up of Co[P{sub 4}Mo{sub 6}]{sub 2} units as the structural motif covalently linked by [Co(Hdien)] complex subunits to yield an unusual 1-D chain. Compounds 2 and 3 are isomorphic and both display covalent discrete M[P{sub 4}Mo{sub 6}]{sub 2} cluster structures which are linked by the hydrogen bonds to form 3-D supramolecular networks. Both 1 and 2 display antiferromagnetic interaction and these three compounds all exhibit intensive photoluminescence. - Graphical abstract: Three new reduced molybdophoshpates based on P{sub 4}MO{sub 6} building blocks have been hydrothermally synthesized. 1 is the first covalent 1-D chain consisting of two kinds of forms of M[P{sub 4}MO{sub 6}]{sub 2} units, standing forms A and lying forms B, while 2 and 3 possess 3-D supramolecular network structures. These three compounds all display photoluminescence.

A simple and effective synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives from aldehydes, 1,3-dicarbonyl compounds and urea or thiourea using chloroacetic acid as catalyst under solvent-free conditions is described. Compared with the classical Biginelli reaction conditions, this new method has the advantage of good to excellent yields and short reaction time.

A simple one-step hydrothermal method for large-scale synthesis of ultralong single-crystalline Bi2S3 nanowires was reported, and the nanowires were comprehensively characterized. The diameters of the nanowires are about 60 nm, and their lengths range from tens of microns to several millimeters. The structure of the nanowires was determined to be of the orthorhombic phase, the growth direction was along [001], and the growth mechanism was investigated based on extensive high-resolution transmission electron microscopy observations. Optical absorption experiments revealed that the Bi2S3 nanowires are narrow-band semiconductors with a band gap E(g) approximately 1.33 eV. Electrical transport measurements on individual nanowires gave a resistivity of about 1.2 ohms cm and an emission current of 3.5 microA at a bias field of 35 V/microm. This current corresponds to a current density of about 10(5) A/cm2, which makes the Bi2S3 nanowire a potential candidate for applications in field-emission electronic devices.