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The article explains a new approach, where in a thiominium salt is employed for the selective conversion of alcohols into alkyl iodides. The method is shown to be extremely beneficial, as it leads to a good yield of the iodides with straightforward purification.

A mild, high-yielding procedure for the preparation of [beta]-ketophosphonates is described. The general condensation and reaction procedure with simple operation could be modified for large-scale preparations of ester and phosphonate.

Septet 2,4,6-trinitrenotoluene as the major paramagnetic product formed during the photolysis of 2,4,6-triazidotoluene in cryogenic matrices which displays different electron paramagnetic resonance (EPR) spectra in solid argon and in 2-methyltetrahydrofuran (2MTHF) glass is reported. The significant changes of the spin densities on the three nitrene units due to interactions of the nitrogen atom with surrounding 2MTHF molecules demonstrated the very small parameter [E.sub.S] in 2MTHF glass.

Heating [K.sub.4][Mo.sub.2][Cl.sub.8] and 2 equiv of Li[RC[(NDipp).sub.2]] (R = H, Ph; Dipp = 2,6-i-[Pr.sub.2][C.sub.6][H.sub.3]) in tetrahydrofuran (THF) has given two paddlewheel type quadruply bonded dimolybdenum complexes. Density functional theory (DFT) calculations are used for corroborating the Mo-Mo quintuple bonding characters.

The decarboxylative nucleophilic addition reactions of malonic acid half thioesters (MAHTs) and malonic acid half oxyesters (MAHOs) with ketone and aldehyde electrophiles in the presence of stoichiometric or catalytic quantities of triethylamine at room temperature are described. The mechanistic insights gained through the studies could be employed in the development of a new decarboxylative coumarin synthesis.

The chiral trans-cyclohexanediamine-benzimidazole organocatalysts were used to promote the conjugate addition of a wide variety of 1,3-dicarbonyl compounds such as malonates, ketoesters, and 1,3-diketones to nitroolefins in the presence of TFA as cocatalyst in toluene as solvent at rt or 0 degree [Celsius]. The DFT calculations indicated that the protonated tertiary amine from the cyclhexanediamine backbond activated the nitroolefin, while the benzimidazole unit activates the 1,3-dicarbonyl nucleophile.

Total synthesis of m ontanacin E and its three diastereomers which involve stereoselective formation of the tetrahydrofuran ring by a cascade cyclization of hydroxy tosylate and an intermolecular cross metathesis between a tetrahydrofuran and a [gamma]-lactone is described. The spectroscopic data and biosynthetic hypothesis of montanacin E provide insight into the inhibitory activities of montanacin E and its isomers against six human solid tumor cell lines.

A combined computational and [super 13]C nuclear magnetic resonance (NMR) study is performed to determine the solution structures of 1-methoxyallenyllithium. The 1-methoxyallenyllithium aggregated hexamer is found to be consistent with a dimmer-tetramer equilibrium.

The preparation of 2-C-branched erythritol derivatives, including the plant sugar ([plusmn])-2-C-methylerythritol, is obtained by a dihydroxylation/reduction sequence on a series of 4-substituted 1,2-dioxines. The asymmetric dihydroxylation of 1,2-dioxines is examined and the 1,2-dioxanes are converted to other erythro sugar analogues and tetrahydrofurans through controlled cleavage of the endoperoxide linkage.

An asymmetric synthesis of anti-aldol segments via a nonaldol route is described, where the strategy has involved a highly diastereoselective synthesis of functionalized tetrahydrofuran derivatives from optically active 4-phenylbutyrolactone. The utility of the method is shown by preparing statine derivatives and pancreatic lipase inhibitor, (-)-tetrahydrolipstatin.

The enzyme subtilisin Carlsberg is surfactant-solubilized into two organic solvents, isooctane and tetrahydrofuran, and hydrated through changes in the thermodynamic water activity ([a.sub.w]). The results have shown that favorable dynamic and electrostatic effects have contributed to accelerated catalysis by solubilized subtilisin Carlsberg upon hydration in organic solvents.

The (salen)Co(III) complexes are used for catalyzing the catalytic enantioselective intramolecular ring-opening of oxetanes with alcohols. This method has produced enantioenriched 3-substituted tetrahydrofurans and has extended the range of electrophiles that can be activated toward highly enantioselective addition reactions by (salen)metal catalysts to an important new class.

The regio- and stereoselective oxidative cyclization of trienes and dienynes containing one electron-deficient double bond in the presence of permanganate ion to yield 2,5-bis-hydroxyalkyltetrahydrofurans (THF diols) is described. The THF diols obtained might serve as convenient precursors to adjacent bis-THFs and the total synthesis of the Annonaceous acetogenin membrarollin.

The synthesis of two trisubstituted epimeric tetrahydrofurans was performed to gain insight into the relative stereochemistry of the natural product aureonitol. The results obtained confirmed that isolated (-)-aureonitol contains the (2S,3R,4S) absolute configuration of stereocenters on the tetrahydrofuran ring.

A novel Prins-type cyclization method and the stereochemistry of terminally substituted alkynyl alcohols for the synthesis of 6-exocyclization to yield cis-2,3,6-trisubstituted tetrahydropyrans is described. The newly developed method opens pathways to design functionalized heterocyclic frameworks.

Directional growth of tetrahydrofuran (THF) clathrate hydrates is analyzed in a mixture of glass beads and a stoichiometric THF-water solution. The increase in the growth rate has resulted in the formation of new layers, leading to the eventual formation of a periodic layered pattern.

The acidic cyclization of 5-alkene-1,2,4-triol derivatives are employed for the stereoselective synthesis of 3-oxygenated-cis-dialkyl-2,5-substituted tetrahydrofurans. The choice of the protecting groups and the reaction conditions are shown to highly affect the product distribution in the system.

The synthesis, structure and pseudorotation of a family of cyclotetraphosphinophosphonium ions are described. The [P.sub.5][H.sub.6.sup.+] and [P.sub.5][Me.sub.6.sup.+] potential surfaces are quantitatively very different from that of the tetrahydrofuran.

Chiral heterocyclic structures based on 3-aminopyrrolidines (3APs), 3-aminotetrahydrothiophens (3ATTs) and 3-aminotetrahydrofurans (3ATFs) are prepared. A general concept is described for rationalizing the process of induction in the presence of organolithium species.

A study report on charge separation and recombination across the full series of four doubly bridgehead substituted benzo-annulated 1,4-disubstituted bicyclo-[2.2.2]octane (BCO) group is presented. The transient absorption spectra obtained in 2-methyltetrahydrofuran (MTHF) showed that all charge transfer rates increases significantly upon cooling the MTHF solutions to their glassy state.

Advanced electron microscopy is used for determining chemical composition and structure as a key step in the analysis of the success of a selection pressure in RNA-mediated evolutionary materials synthesis. It is shown that RNA selections should not be carried out in binary solvent systems, such as tetrahydrofuran (THF) and water.

The synthesis and structural characterization of tetrahydrofuran C[alpha]-tetrasubstituted amino acids from methionine is described. The reaction induces two consecutive [beta]-turns as part of a tripeptide of aliphatic [alpha]-amino acids.

The structures and reactivity of metal hydride complexes dissolved in tetrahydrofuran (THF) are studied. The acidity of these complexes involving different metals shows an increase according to the position of metals in the periodic table.

The scope and characteristics of rhenium(VII) oxide catalyzed heteroacylative ring-opening dimerization of tetrahydrofuran (THF) are described. It is shown that in the presence of trifluoroacetic anhydride (TFAA) and a carboxylic acid at room temperature, [Re.sub.2][O.sub.7] catalyzes the ring-opening of THF to produce a nonsymmetrical diester at room temperature.

Aluminumoxyhydride (HAIO) is obtained by the reaction of aluminum hydride with the siloxane [(Me2HSi).sub 2]O or the stannoxane [(Bu3Sn).sub. 2)O as an amorphous colorless insoluble powder. The resulting suspensions from the reaction are 0.4-0.5 M in active hydride content and they selectively reduce aldehydes and ketones to the respective alcohols in the presence of any other common nonprotic functional group.

The preparation of a series of mixed-ligand hexanuclear Li aggregates, which react with Lewis basic solvents such as tetrahydrofuran (THF) and hexamethylphosphoramide (HMPA) to afford novel solvent-solvated lithium alkoxide aggregates is reported. In the presence of Lewis basic solvents such as THF and HMPA, hexanuclear Li complexes engender rearrangement and solvation to yield various kinds of solvated Li aggregates, with their nuclearities being dramatically dependent on the basicity of the solvent.

Cyclo-(Taa1-Leu-Val)2, cyclo-(Taa2-Leu-Val)2, and cyclo-(Taa2-Phe-Leu)2 displayed well-defined distorted beta-beta corner structures. Such oligomeric assemblies, with intramolecularly hydrogen-bonded structures could play significant roles in recognizing and binding to suitable ligands mimicking biological systems.

The time-space average filling of hydrogen molecules in a binary tetrahydrofuran (THF)-d8 + D2 sII clathrate hydrate is determined using high resolution neutron diffraction. The hydrogen molecules are localized in the small dodecahedral cavities at 20 K, with nuclear density from the hydrogen approximately spherically distributed and centered in the small cavity.

An alternate strategy is presented, to prepare 2,3-disubstituted tetrahydrofurans based on the group transfer reactions of S-alkyl dithiocarbonates (xanthates) followed by their substitution. From 2,3-dihydrofuran derivatives, the displacement of the resulting anomeric xanthates with various nucleophiles in the presence of Lewis acid allowed the formation of new carbon-carbon and carbon-heteroatom bonds.

The inhibition activities of two antifreeze proteins (AFPs) on the formation of tetrahydrofuran (THF) clathrate hydrate are examined. The AFPs from fishes and insects change the crystal habit of THF hydrate and also inhibit hydrate crystal growth and inhibitors based on AFPs are likely to find utility in the prevention of unscheduled hydrate growth.

A fast and efficient synthesis of the cytotoxic natural agent, pachstrissamine, and its unnatural 4-epi-congener, starting from phytosphingosine is described. The natural product pachastrissamine was synthesized in three steps and with 72% overall yield from D-ribo-phytosphingosine.

The templated synthesis of cadmium sulphide (CdS) quantum dots (QDs) located in aggregates of poly(ethylene oxide)-block-polystyrene-block-poly (acrylic acid) triblock copolymers, which display different morphologies, depending on the experimental and preparative conditions is described. It is demonstrated that the same triblock copolymer, after cross-linking with Cd(super 2+), can assemble into several distinct morphologies, depending on the solvent used, tetrahydrofuran (THF) or water and the sequence of steps involved.

The crystal structure of tetrahydrofuran deuterate, a clathrate hydrate, is refined from neutron powder diffraction data at five temperatures in the range 7-265K. The most pronounced structural changes occur in a similar regime of T as changes in guest dynamics observed in spectroscopic and thermodynamic studies.

The self-assembled structures by evaporation of tetrahydrofuran (THF) solution of wire-type dendrimers are studied. Polarization and local fluorescence measurements at some parts of doughnuts and particles are demonstrated.

Icosaniobate [[[Nb.sub.20][O.sub.54]].sup.8-] is synthesized by reacting [[[H.sub.4][Nb.sub.6][O.sub.19]].sup.4-] with NO in tetrahydrofuran or MeN[O.sub.2]. A single crystal X-ray diffraction study of its n-tetrabutylammonium salt has revealed a dimeric structure, where two decaniobate ions are condensed sharing two terminal O atoms.