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With the increasing of the quantity of the tunnel, more and more attentions have been paid to the tunnel destruction induced by earthquake. Based on the software of finite element, the finite element model for deeply buried tunnel have been set up; and the responses about different rigidity of tunnel lining under seismic dynamic load has been analyzed by using elastic finite element theory. The conclusions have been drawn that the change of seismic responses by increasing rigidity of tunnel lining is unobvious, and the method using increasing rigidity of tunnel lining to reduce the seismic responses of tunnel is uneconomical.

An accelerated, enantioselective, and general synthetic route to a class of malyngamides, K (1), L (3), and 5''-epi-C (4), bearing a cyclohexenone ring or a heavily oxygenated six-membered ring and a vinyl chloride structural motif was developed. The key step was the Suzuki cross-coupling reaction of boronic acids 6-8 with unsaturated carboxylic amides 5a,b possessing the chlorovinyl iodide functionality for the construction of the skeletons of 1-4. The key intermediates 10a,b were prepared using Ogilvie's method for the construction of the chlorovinyl iodide functionality. The NMR data of the synthetic compound 2 were in full agreement with those of the reported product, and the discrepancy in the specific rotation data suggested that the correct structure of malyngamide L should be 3, in which the absolute configuration of the amine part was enantiomeric to that in compound 2. Then the absolute configuration of the stereogenic center at C(3'') and C(4'') in malyngamide L was confirmed by synthesis of compound 3.

The synthesis of several inherently chiral tribenzotriquinacenes (TBTQs) bearing one single mono- or difunctionalized aromatic nucleus and the optical resolution of one of these derivatives, a TBTQ-based salicylic acid (11), are described for the first time. Efficient access to enantio-pure, inherently chiral tribenzotriquinacenes may lay a foundation for studies of novel container compounds, supramolecular aggregation, chiral recognition, and asymmetric catalysis.

Unsymmetrical dendrons 1, 2 and 3 were easily prepared according to a novel convergent strategy from 3, 4-methylene-dioxybenzaldebyde as starting material.

The Ramberg-Backlund rearrangement has been successfully utilized to convert readily available α- and α'-hydrogen bearing substituted dibenzyl sulfones into corresponding stilbene derivatives, which is conveniently followed by hydrogenation in the presence of 10% Pd/C to afford the natural bibenzyls.

The stereoselective synthesis of malyngamide M (1) was accomplished in nine steps from o-cresol in 12% overall yield. The key steps involved the Wittig reaction of an α-NHBoc aryl ketone 4 for the introduction of vinyl chloride functionality, an amidation of lyngbic acid 3 with a secondary amine 2 for the framework of target molecule, and an isomerization of a (Z)-vinyl chloride to the (E)-configuration using benzophenone as a photosensitizer. The isomalyngamide M (Z-1) was also synthesized.

Single-component monolayer of novel multi-thiol coronary molecule and two-component mixed monolayer composed of coronary molecule and n-alkanethiol on gold substrates are described. The assembly of monolayers is characterized by ellipsometry, infrared spectroscopy and X-ray photoelectron spectroscope. The electrochemical properties of the single- and two-component monolayers are evaluated by cyclic voltammetry and electrochemical impedance spectroscopy experiments. Coronary molecule with multi-thiol groups has the ability to form stable monolayer via the interaction of mercapto groups and Au surface. Electrochemical impedance measurements indicate that 89.9% of the gold surface is blocked by the coronary molecule, which is attributed to the special spatial structure of the coronary molecule. The uncovered site on gold surface in coronary molecule monolayer could be occupied by the second suitable molecule. The mixed monolayer prepared by stepwise assembly of coronary molecule and n-alkanethiol has complete compact packing and few defects.

A series of amphiphilic dendrons (G1-G4) have been designed and synthesized, which have a highly branched aliphatic hydrocarbon skeleton and a hydrophilic hydroxyl functionality to enable conjugation with other substrates. The higher generation dendrons (G3 and G4) were synthesized by a double-stage convergent method, which shortened the synthetic route significantly and provided the products in an efficient manner. The key branching step involved a double alkyl-metal addition to an ester functionality followed by deoxygenation of a resulting tertiary alcohol by triethylsilane.

A convergent, enantioselective and general synthetic route to a class of marine natural products-malyngamides O (1), P (2), Q (3), R (4), 5''-epi-3 and 5''-epi-4-bearing a novel vinyl chloride structural motif was developed. The key steps involved construction of the vinyl chloride functionality by Wittig reaction, a DCC/HOBt-promoted amidation, an aldol reaction in the construction of the basic backbone of 1, 2, 3, 4, 5''-epi-3, and 5''-epi-4, and methylation of an enol moiety via either base/acid conditions or a Mitsunobu reaction. Moreover, the absolute configuration of the stereogenic center at C-5'' in 3 was further confirmed by synthesis of the natural product and its C-5'' epimer.

A series of tridentate NNN iron(II) and cobalt(II) dichloride complexes bearing 2-(1H-2-benzimidazolyl)-6-(1-(arylimino)ethyl)pyridines were synthesized and characterized by elemental and spectroscopic analyses. Single-crystal X-ray diffraction studies of representative examples of the cobalt and iron complexes confirm distorted bipyramidal geometry around the metal center. Upon coordination of a methanol solvent molecule, a geometry change to distorted octahedral was observed. The steric and electronic effects on catalytic activity are evaluated for different substituents in the arylimino part of the ligand: Me, Et, iPr, Cl, and Br in ortho- and Me and H in para-position. On treatment with methylaluminoxane (MAO) or modified MAO (MMAO), the iron(II) complexes exhibited good activities of up to 106 g·mol−1(Fe)·h−1 for ethylene oligomerization and moderate activities for polymerization, while cobalt(II) complexes showed moderate activities for ethylene dimerization. The best activities were observed with...

Iodophenyl-terminated organic monolayers were prepared by thermally induced hydrosilylation on hydrogen-terminated silicon (1 1 1) surfaces. The films were characterized by ellipsometry, contact-angle goniometry, and X-ray photoelectron spectroscopy (XPS). To modify the surface chemistry and the structure of the monolayers, the Sonogashira coupling reaction was performed on the as-prepared monolayers. The iodophenyl groups on the film surfaces reacted with 1-ethynyl-4-fluorobenzene or the 1-chloro-4-ethynylbenzene under the standard Sonogashira reaction conditions for attaching conjugated molecules via the formation of C C bonds. It is expected that this surface coupling reaction will present a new method to modify the surface chemistry and the structure of monolayers.

The 2-alkoxyimidate-1,10-phenanthroline complexes of manganese, cobalt and nickel have been synthesized by the reaction of 2-cyano-1,10-phenanthroline with metal dichloride in the corresponding alcohol. The metal complexes bearing two 2-cyano-1,10-phenanthrolines were isolated in non-protonic solvent as the coordination around metal core with two ligands and two chlorides. The alkoxyimidation of nitrile linked on ligand was speeded in forming the 2-alkoxyimidate-1,10-phenanthrolinyl metal complexes. All the complexes have been characterized by FT-IR spectra and elemental analysis, and some of their structures have also been confirmed by single-crystal X-ray diffraction analysis. All the metal complexes were evaluated in the catalytic oligomerization of ethylene with some alkylaluminums as co-catalyst; in which manganese complexes were less active, cobalt complexes showed low to moderate activities, and nickel complexes gave moderate to good activities.

In this work, the effects of various dendrimer shells on the intermolecular interactions of oligo(phenyleneethynylene)s (OPE) molecular wires in thin films have been studied. Electronic and fluorescence spectra showed that the dendrimer shells can effectively inhibit the aggregation of the molecular wires in both solutions and thin films. Tapping mode atomic force microscopy (TM-AFM) revealed that with the increase of dendrimer size, the film morphologies changed from fibrous to dendritic, indicating a strong shell-dependent molecular packing. This work demonstrated that such ‘core–shell’ molecular design strategy can be used to precisely tailor the molecular environment surrounding the molecular wires.

(1S,2R,3R,5R,7aR)-1,2-Dihydroxy-3-hydroxymethyl-5-methylpyrrolizidine(hyacinthacine A 6 , 1) was synthesized by Wittig's methodology via the reaction of aldehyde 6, prepared from the partially protected derivative of polyhydroxylated pyrrolidine, with appropriated ylides, followed by cyclization through the internal reductive amination process of the resulting α,β-unsaturated ketone 7, and total deprotection.

An efficient and facile synthesis of phytosphingosine and dihydrosphingosine derivatives is described with less steps and in improved overall yield (66–72%) starting from commercially available tri-O-benzyl-D-galactal. The key steps include Wittig reaction, Mitsunobu transformation, reduction, and deprotection.

Solid complexes of terbium, neodymium and yttrium nitrates with an amide type ligand, N-benzyl-2-(benzyloxy)benzamide (L) have been prepared in ethyl acetate and characterized by elemental analysis and IR spectroscopy. The crystal and molecular structures of the complexes TbL3(NO3)3, NdL3(NO3)3 and YL3(NO3)3 have been determined by single crystal X-ray diffraction. The crystal structures of the complexes are similar. The structures show that the crystal consists of two similar but independent molecules in the asymmetric unit and the metal ion is coordinated toward nine donor atoms, three of which belong to the oxygen atoms of three monodentate ligands and six oxygen atoms from three bidentate nitrates. Furthermore, the REL3(NO)3 complex units are linked by the intermolecular hydrogen bonds to form a three-dimensional net. At the same time, the luminescent properties of the ligand and the complex TbL3(NO3)3 were studied as well.

An efficient method for the construction of cyclopropane-fused dihydroquinolines was established by a novel Povarov-type three-component reaction of aromatic aldehydes, anilines and cyclopropenes in the presence of trifluoromethanesulfonic acid. The reaction proceeded in a regioselective and diastereoselective manner. Furthermore, the dihy-droquinolines were smoothly converted to benzazepine derivatives via a ring opening/isomerization sequence, further expanding the synthetic scope.

Through a surprisingly nonregioselective oxidation process, the reaction of two analogous 2-hydroxy-substituted tribenzotriquinacenes (TBTQs) 8a/8b by o-iodoxybenzoic acid was found to afford the corresponding C-s- and C-1-symmetrical TBTQ-o-quinones 6a/6b and 7a/7b, respectively, in 1:1 ratio and excellent combined yields. This finding represents the first example of direct introduction of a functional group into a sterically hindered, inner bay-positions of a parent TBTQ skeleton. In contrast, the analogous reaction with 1-hydroxy-TBTQ 15 failed to produce the desired o-quinone 7a. After reduction of the quinones 6a and 7a to the corresponding catechols 17 and 23, electrophilic aromatic substitution could also be realized at the activated inner bay-position(s) to afford several tri- and tetrafunctionalized TBTQ compounds 18, 21, and 25. The C-s-symmetrical o-quinone 6a was converted into further single-wing extended derivatives such as TBTQ-based phenazines 27a-f, through condensation reactions, and to benzodioxine derivative 32 by Diels-Alder reaction with tetracyclone. The novel TBTQ: quinones and the corresponding TBTQ-catechols offer a variety of new accesses to single-wing-extended and functionalized TBTQ derivatives.

A series of alkyl-substituted tetraazacyclododecane congeners were synthesized, and their antitumor activities towards human HeLa cells as well as their effect on the in vitro transcription with T7 RNA polymerase were investigated. A structure-activity-relationship (SAR) study identified the most-active congeners as those with medium alkyl-chain lengths. Three compounds, 5-7, were found to exhibit significant biological activities, with IC50 values towards HeLa cells in the low-micromolar range.

The first examples of novel bowl-shaped tribenzotriquinacenes (TBTQs) bearing three dithiametacyclophane units within their arene peripheries are reported. The synthesis is based on a C-3v-symmetrical hexakis(chloromethyl)tribenzotriquinacene as the key intermediate and yields the inter-ring metacyclophane-type macrocyclization instead of the intra-ring orthocyclophane-type cyclocondensation. Multiple nucleophilic substitution of the same key intermediate leads to a number of other new 6-fold functionalized tribenzotriquinacenes, some of which may be of interest as readily accessible building blocks for the construction of novel bowl-shaped organic networks. The molecular structures of the novel tris(dithiametacyclophanes) and of the hexakis(chloromethyl)- and hexakis(hydroxymethyl)tribenzotriquinacenes have been determined by X-ray analysis and interesting host/guest aggregation and torsional effects in the solid state are discussed.

The two partially protected pyrrolidines (2 R,3 S,4 R,5 S)- and (2 R,3 S,4 R,5 R)-3,4-bis(benzyloxy)-2-[(benzyloxy)methyl]-5-[( TERT-butyldimethylsiloxy)methyl]pyrrolidine were synthesized from D-glucose as precursor in the stereoselective synthesis of hyacinthacines. The key strategies were the ring opening of the sugar epoxide with sodium azide to convert the configuration at C-2 and C-3 of D-glucose and simultaneous reduction and intramolecular cyclization. 5- EPI-Hyacinthacine A 4 was synthesized from the (2 R,3 S,4 R,5 S)-pyrrolidine by Wittig reaction and cyclization.

Superhydrophobic surfaces on engineering materials are prepared via a convenient solution-immersion method. The binary geometric structures at the micro- and nanometer scale bestow superhydrophobic properties on the surfaces. The surfaces show stable superhydrophobicity even in many corrosive solutions, such as acidic or basic solutions over a wide pH range, and also in salt solutions. The procedure is time-saving, inexpensive, and fairly facile to carry out. It is expected that this facile technique will accelerate the large-scale production of superhydrophobic engineering materials with new industrial applications.

Two series of oligo(phenylene ethynylene)s (OPEs) with different dendrimer side groups have been designed and synthesized. The molecules contain thiol groups at both ends to enable interconnection between nanoscale gapped metallic electrodes. The different dendrimer groups act as "shells", allowing tailoring to the nanoscopic environment surrounding the OPE "core". Meanwhile, the dendrimer shells also act as spacers for the precise control of the packing density and intermolecular interaction between the OPE cores. [structure: see text].

Several alkyl-substituted mesocyclic diamines were synthesized, and their interaction with DNA were studied by melting-temperature measurements and the ethidium bromide (EB)-fluorescence competitive method. The supercoiled DNA hydrolytic cleavage by 1,4-dioctyl-1,4-diazepan-6-ol (4) was supported by the evidence from free-radical quenching and T4-ligase ligation. Preliminary pharmacological tests showed that only 1,4-dioctyl-1,4-diazepan-6-ol (4) had antitumor activity against HeLa cell lines in vitro.

Sialylconjugates on cell surfaces are involved in many biological events such as cellular recognition, signal transduction, and immune response. It has been reported that aberrant sialylation at the nonreducing end of glycoconjugates and overexpression of sialyltransferases (STs) in cells are correlated with the malignance, invasion, and metastasis of tumors. Therefore, inhibitors of STs would provide valuable leads for the discovery of antitumor drugs. On the basis of the transition state of the enzyme-catalyzed sialylation reaction, we proposed that the cyclopentane skeleton in its two puckered conformations might mimic the planar structure of the donor (CMP-Neu5Ac) in the transition state. A series of cyclopentane-containing compounds were designed and synthesized by coupling different cyclopentane α-hydroxyphosphonates with cytidine phosphoramidite. Their inhibitory activities against recombinant human ST6Gal-I were assayed, and a potent inhibitor 48l with a Ki of 0.028 ± 0.006 μM was identified. The results show that the cyclopentanoid-type compounds could become a new type of sialyltransferase inhibitors as biological probes or drug leads.

Background We aimed to systematically review the efficacy of mannitol (MTL) on patients with acute severe traumatic brain injury (TBI). Methods Databases such as PubMed (US National Library of Medicine), CENTRAL (The Cochrane Library 2014, Issue 3), ISI (Web of Science: Science Citation Index Expanded), Chinese Biomedicine Database (CBM), and China Knowledge Resource Integrated Database (CNKI) have been searched for relevant studies published between 1 January 2003 and 1 October 2014. We have established inclusion and exclusion criteria to identify RCTs, which were suitable to be enrolled in the systematic review. The comparison group could be hypertonic saline (HS), hydroxyethyl starch, or others. The quality assessment was based on the Cochrane Handbook for Systematic Reviews of Interventions Version 5.0.1 and modified Jadad score scale. The major outcome was mortality, followed by the secondary outcomes such as neurological outcome, days on intensive care unit (ICU), and ventilator day. In addition, intracranial pressure (ICP), cerebral perfusion pressure (CPP), and mean arterial pressure (MAP) were used as the surrogate endpoints. Data synthesis and meta-analysis was conducted by using R (version 3.7-0.). Results When 176 potential relevant literatures and abstracts have been screened, four RCTs met all the inclusion criteria and were enrolled for the meta-analysis. Amongst all the enrolled studies, two trials have provided the primary outcome data. There was no heterogeneity between two studies (I2 = 0 %) and a fixed model was used for meta-analysis (n = 53), pooled result indicated that the mortality was similar in mannitol intervention and control treatment, OR = 0.80, 95 % CI [0.27, 2.37], P = 0.38. We found that both mannitol and HS were efficient in decreasing the ICP. Furthermore, the effect of the HS on the ICP appeared to be more effective in the patients with diffuse brain injuries than mannitol did. Conclusions As a conclusion, the mannitol therapy cannot reduce the mortality risk of acute severe traumatic brain injury. Current evidence does not support the mannitol as an effective treatment of acute severe traumatic brain injury. The well-designed randomized controlled trials are in urgent need to demonstrate the adoption of mannitol to acute severe traumatic brain injury.

A series of methylidene substituted 2,5-dihydrofurans is prepared via the reaction of ethyl 5,5-diphenylpenta-2,3,4-trienoate (I) with aryl or hetaryl aldehydes.

The selective electroanalysis of dopamine (DA) using the self-assembled monolayers of an oligo(phenyleneethynylene)s (OPEs) type molecular wire have been studied for the first time. Cyclic voltammetry measurement showed the OPE modified electrodes preferentially inhibit the electrochemical reaction of ascorbic acid (AA). Using square-wave voltammetry technique, DA was quantitatively determined in the presence of high concentration AA. This work reveals that, besides molecular electronics, biosensor could be an attractive new field of application for the OPE type molecular wires. Keywords: Self-assembled monolayers (SAMs), Molecular wires, Dopamine, Modified electrodes, Oligo(phenylene ethynylene) (OPE)

This paper described a concise construction of (−)-EGCG (1f) (with an overall yield of 20% for seven steps based on the starting cinnamyl alcohol derivative 3), featuring asymmetric dihydroxylation (ADH), intra- and inter- molecular Mitsunobu reaction as key steps. Our strategy disclosed herein constitutes a new effective general synthetic approach toward the analogues of (−)-EGCG (1f).

A stereoselective synthesis of 1a { N -[(1 R )-2-hydroxy-1-methoxy-methyl ethyl]-(4 E ,7 S )-7-methoxy-4-eicosenamide} has been accomplished in 10 steps from 1-tetradecanol for the first time in 28% overall yield. The key steps involved the coupling reaction of a chiral alkyne with a protected bromide in the presence of t -BuLi, as well as the amidation reaction of (4 E ,7 S )-7-methoxyeicos-4-enoic acid with ( R )-methoxyamino alcohol. Acetylation of 1a finished the preparation of 1b { N -[(1 S )-2-acetyloxy-1-methoxy-methyl ethyl]-(4 E ,7 S )-7-methoxy-4-eicosenamide}. Their 1′- epi -isomers have also been synthesized with a similar strategy.

A stereoselective synthesis of (4E,7S)-(-)-7-methoxydodec-4-enoic acid has been accomplished in eight steps from hexanal in 24% overall yield. The key steps involved the catalytic asymmetric allylation of hexanal and the coupling reaction of a chiral alkyne and a protected bromide in the presence of t-BuLi.

Long chain branched dendrimers 1,2 and 3were easily prepared according to the convergent strategy based on the A2B type monomer from 5-hydroxyisophthalic acid. These dendrimers have a nucleophilic phenol focal group, which is useful to further chemistry.

Phebaclavin A (1) and C (2) were synthesized in 60% and 58% total yields over 5 steps from commercially available starting meterials respectively. The synthesis feature was usage of the Wittig reaction twice and solvent-free cyclizing reaction as the key steps.

Highly efficient six- and eightfold Heck cross-coupling reactions were carried out with two related convex-concave and saddle-shaped hydrocarbons bearing several ortho-dibromo functionalities at the molecular periphery, viz. the hexabromotribenzotriquinacene 3a and the octabromofenestrindane 4a. In contrast to conventional palladium catalysts, use of Najera's oxime-derived palladacycle catalyst 7 effected exhaustive vinylation with styrene or methyl acrylate in high yield and without concomitant formation of partial cross coupling or reduction products, The hexavinyltribenzotriquinacenes and octavinylfenestrinddnes thus obtained are of interest as potential building blocks for novel organic networks, ((c) Wiley-VCH Verlag GmbH & Co, KGaA, 69451 Weinheim, Germany, 2005)

A convenient and rapid approach for the synthesis of naturally occurring unsaturated amide alkaloids 1a–1n by the recently developed one-flask Ramberg–Bäcklund reaction is described. The starting material was alcohol 3, which was transformed into thiolacetate 4 using the Mitsunobu reaction. In situ cleavage of acetyl moiety of 4, followed by alkylation of the resulting thiol with appropriate chloroacetamide 5, provided the sulfide 6. Oxidation of sulfide 6 gave the corresponding sulfone 2. Treatment of the sulfone 2 with the dibromodifluoromethane in the presence of alumina-supported potassium hydroxide in dichloromethane solution afforded unsaturated amide alkaloids 1a–1n. To the best of our knowledge, the synthesis of 1e and 1i was reported for the first time.Key words: synthesis, unsaturated amide alkaloids, Ramberg–Bäcklund reaction.

The reaction of allylic dienylic sulfone with dibromodifluoromethane in the presence of alumina-supported KOH in dichloromethane solution results in facile rearrangement affording the corresponding all- trans 1,3,5,7-octatetraenes in excellent yields. This result shows that the double bonds of stereochemically defined allylic dienylic sulfone retain their stereochemistry and the newly formed double bond has an ( E )-configuration in the modified Ramberg–Backlund procedure.

The novel convergent growth approach to dendritic macromolecules is described. Polyether dendritic sectors [G-na]-OH from the first to the fourth generations, respectively, were prepared by this approach from readily available starting material.

A Lewis acid promoted tandem reaction of epoxide rearrangement and intramolecular [3+2] cycloaddition reaction of cyclopropanes with carbonyls formed by epoxide rearrangement in situ, which were obtained with difficulty by a general method, is reported. A wide variety of fused- and spiro-oxa-[n.2.1] skeletons could be efficiently constructed.

The regiocontrolled syntheses of four chiral C-1- or C-3-symmetrical tribenzotriquinacene (TBTQ) derivatives bearing methoxy or hydroxy groups at the peripheral positions [(2,6-(OMe)(2), (+/-)-18 and (+/-)-20; 2,6-(OH)(2), (+/-)-19; and 2,6,10-(OMe)(3), (+/-)-21] by two different synthesis protocols are reported. Compounds (+/-)-19, (+/-)-20, and (+/-)-21 and two (already-known) monosubstituted C1-symmetrical TBTQ analogues [2-OH (+/-)-23 and 2-OMe (+/-)-24] were readily resolved by chiral HPLC, and their absolute configurations were determined by X-ray crystallography and/or circular dichroism (CD) studies. Optical resolution of three closely related TBTQ derivatives [2,6-(OMe)(2), (+/-)-18; 2-OMe, (+/-)-22; and 2-OH, (+/-)-25] containing the same peripheral substituents but other bridgehead residues failed. Enantiopure TBTQ derivatives of this sort are considered promising structural motifs toward the construction of molecular squares and cubes

A convenient and rapid approach for the syntheses of (-)-kaerophyllin (1), (-)-hinokinin (2) and (±)-isohinokinin (3) was described. The key steps were involved in condensation of aromatic aldehyde and alkylation of the resulting ester to give the complete skeleton of dibenzylbutyrolactone-lignan. Hydrolysis, followed by resolution with quinine, reduction and when appropriate, oxidation gave the title compound. The asymmetric total synthesis of the kaerophyllin (1) was reported for the first time.

A series of 2-(1-(2-benzhydrylnaphthylimino)ethyl)pyridine derivatives (L1-L3) was synthesized and fully characterized. The organic compounds acted as bi-dentate ligands on reacting with nickel halides to afford two kinds of nickel complexes, either mononuclear bis-ligated L2NiBr2 (Ni1-Ni3) or chloro-bridged dinuclear L2Ni2Cl4 (Ni4-Ni6) complexes. The nickel complexes were fully characterized, and the single crystal X-ray diffraction revealed for Ni2, a distorted square pyramidal geometry at nickel comprising four nitrogens of two ligands and one bromide; whereas for Ni4, a centrosymmetric dimer possessing a distorted octahedral geometry at nickel was formed by two nitrogens of one ligand, two bridging chlorides and one terminal chloride along with oxygen from methanol (solvent). When activated with diethylaluminium chloride (Et2AlCl), all nickel complexes performed with high activities (up to 1.22 × 10(7) g (PE) mol(-1) (Ni) h(-1)) towards ethylene polymerization; the obtained polyethylene possessed high branching, low molecular weight and narrow polydispersity, suggestive of a single-site active species. The effect of the polymerization parameters, including the nature of the ligands/halides on the catalytic performance is discussed.

A highly chemoselective one-pot reaction has been developed involving a tandem semipinacol rearrangement/oxa-Michael addition sequence in which the in situ generated ketol diene intermediate can be transformed specifically to either the spiro- or fused-dihydrofuran products (see scheme). This one-pot tandem reaction represents a general synthetic methodology for the syntheses of the two different kinds of furan derivatives.

( E )- and ( Z )-enediynes 7 are readily synthesized in good yields from a one-pot modified Ramberg-Backlund reaction from dipropargylic sulfones 5 .

Based on a regioselective tris-formylation of a tribenzotriquinacene (TBTQ) hydrocarbon, the racemic C(3)-symmetrical TBTQ-trialdehyde and the corresponding TBTQ-trimethanol were synthesized along with their C(1)-isomers. Conversion of the C(3)-trialdehyde to three diastereomeric TBTQ-based cryptophanes occurring in high yield enabled the preparation of the optically pure C(3)-symmetrical TBTQ-trialdehydes and the determination of their absolute configuration. The racemic C(3)-symmetrical TBTQ-trimethanol was found to form several stable nanotubular aggregates in the solid state.