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An efficient one-pot route to unsymmetrical diorganyl selenides is developed by ruthenium(III) chloride catalyzed reactions of dibenzyl or diphenyl diselenodes with alkyl halides in the presence of zinc. Organic iodides, bromides, and activated chlorides underwent the reactions efficiently.

Palladium(II)-catalyzed intramolecular carbonylative cycloisomerization of [gamma]-propynyl-1,3-diketones with aryl iodides and carbon monoxide is used to efficiently synthesize the di- and trisubstituted furan derivatives. The mechanism suggested that in situ generated acylpalladium species from the carbonylation of aryl iodide initiated the reaction followed by cyclization of the enolized isomer of a 1,3-diketone substrate via carbon-carbon triple bond activation.

Efficient regioselective addition of [beta]-diketones to styrenes, norbornene, cyclic enol ether and diene are obtained by using copper(II) triflate as the catalyst. The solvent effect is prominent on the reactions and the mechanism has shown that copper(II) triflate has activated the enolic O-H bond of a [beta]-diketone substrate to initiate the addition reaction.

A new protocol for the rhodium-catalyzed regioselective functionalization of the C-H bonds via the decarbonylation of acid chlorides and C-H bond activation under phosphine-free conditions is discussed. The approach is shown to play an extremely significant role in the organic synthesis applications.

A new method to synthesize mixed bimanes and construct novel N-heterocyclic ring systems from the reactions of 1-alkynyl Fischer carbene complexes [(OC).sub.5]M=C(OEt)C=CPh (M = Cr, W) and substituted pyrazolinones is described. Efficient oxidative demetalation of the newly formed N-heterocyclic Fischer carbene complexes with pyridine N-oxide (PNO) or m-chloroperoxybenzoic acid (m-CPBA) was found to afford strongly fluorescent syn-mixed bimanes and other novel N-heterocyclic compounds.

The synthesis of palladium complexes of two new types of unsymmetrical pyridyl-supported pyrazolyl-N-heterocyclic carbene ligand and the catalytic activity of the palladium complexes in Suzuki-Miyaura reactions are reported. The study reveals that all palladium complexes exhibit good to excellent catalytic activity in Suzuki-Miyaura reactions of phenyl or p-tolylboronic acid with aryl halides including iodobenzene, aryl bromides, and activated aryl chlorides under mild conditions.

An efficient method for the synthesis of symmetrical diselenides is studied. Reductive selenation of aromatic and hetrocyclic aromatic aldehydes (ArCHO) with Se/CO/H(sub 2)O in DMF afforded diselenides yields upto 94 percent under atmospheric pressure without use of base.

Biomimetic recycling of the expensive cofactors NAD(P)H/NAD(P)+ and their models is a promising area in bio-inspired synthesis. This paper highlights the recent advances in the in situ regeneration of the oxidized cofactors NAD(P)+ through oxidation of cofactors NAD(P)H in the presence of an alcohol dehydrogenase by means of dioxygen and a synthetic Fe(III) porphyrin as a biomimetic NAD(P)H oxidase or flavin as catalyst, and biomimetic in situ regeneration of the expensive NAD(P)H models Hantzsch esters (HEH) and 9,10-dihydrophenanthridine (DHPD) by transition-metal and chiral Brønsted acid catalyzed relay asymmetric hydrogenation. [ABSTRACT FROM AUTHOR]

FeCl3- and FeBr3-promoted cyclization/halogenation of alkynyl diethyl acetals has been efficiently realized, selectively affording (E)-2-(1-halobenzylidene or alkylidene)-substituted five-membered carbo- and heterocycles which were then efficiently transformed to vinylarenes by Suzuki coupling. The present protocol has provided a new alternative route to vinylic C−Cl and C−Br bond formation. [ABSTRACT FROM AUTHOR]

A family of hemilabile ruthenium(II) NNN complexes bearing a unsymmetrical 2-(benzoimidazol-2-yl)-6-(pyrazol-1-yl)pyridine ligand has been synthesized and exhibited good to excellent catalytic activity in transfer hydrogenation of ketones in refluxing 2-propanol, reaching final TOFs up to 7.2 × 105h−1with 0.05 mol % loading. The γ-NH effect of the benzoimidazol-2-yl moiety in the ligand and coordination modes of the metal center in a Ru(II) NNN complex has great influence on the catalytic activity of the complex catalyst in transfer hydrogenation of ketones. It has been demonstrated that one of the structural prerequisites for an active Ru(II) complex catalyst is the coordinatively unsaturated environment around the metal center in the complex or the precatalyst, and the catalytic activity of a complex catalyst can be enhanced by making its metal center cationic. This paper presents a methodology to construct new types of efficient Ru(II) complex catalysts for transfer hydrogenation of ketones. [ABSTRACT FROM AUTHOR]

Efficient rhodium(I)-catalyzed regioselective direct arylation and alkenylation of aromatic C−H bonds has been realized with aromatic carboxylic and cinnamic anhydrides as the coupling partners via decarbonylation and C−H activation under phosphine-free conditions. [ABSTRACT FROM AUTHOR]

Ruthenium(II) complexes bearing a pyridyl-supported pyrazol-3-yl−N-heterocyclic carbene (NNC) ligand were synthesized from the reactions of RuCl 3·3H 2O with pyridyl-supported pyrazol-3-yl−imidazolium salts in the presence of carbon monoxide. These Ru(II) complexes have exhibited good to excellent catalytic activity in the transfer hydrogenation of ketones in refluxing 2-propanol. Formation of a coordinatively unsaturated Ru(II) center in the precatalyst is attributed to the high catalytic activity of the Ru(II) complexes. [ABSTRACT FROM AUTHOR]

Reactions of ferrocenyl−(CH 2) n-bridged bis(pyrazoles) with nickelocene afforded inter- and intramolecular dimeric poly(heteronuclear) cyclopentadienylnickel(II) complexes from which a novel toluene-embodied guest−host system was obtained by π-interaction. The present paper has demonstrated a new class of potentially useful organometallic building blocks for supramolecular assembly and the first example of a pyrazolato ligand exhibiting a charge transfer type π-interaction. [ABSTRACT FROM AUTHOR]

Rare ruthenium(II) complexes bearing a pyridyl-based pyrazolyl−imidazolyl ligand were synthesized and exhibited exceptionally high catalytic activity in the transfer hydrogenation of ketones in 2-propanol at 82 °C or room temperature, reaching 100% conversion of the substrates and final TOFs up to 7.2 × 10 5h −1with 0.05 mol % catalyst at 82 °C and 55 800 h −1with 0.1 mol % catalyst at room temperature. [ABSTRACT FROM AUTHOR]

An efficient method for the synthesis of sym- metrical diselenides is described. Reductive selenation of aromatic and heterocyclic aromatic aldehydes (ArCHO) with Se/CO/H2O in DMF afforded diselenides (ArCH2SeSeCH2- Ar) in yields up to 94% under atmospheric pressure without use of a base. [ABSTRACT FROM AUTHOR]

Reports on the desilylation of tert-butyldimethylsilyl (TBDMS) ethers of primary, secondary and tertiary alcohols and phenolic TBDMS ethers to their corresponding alcohols and phenols, respectively. First examples of desilylations of silyl ethers catalyzed by nonionic bases; Possible pathways involving nucleophilic attack of the anion of the solvent molecule.

CuCl2 and CuBr2-mediated intramolecular oxidative C-H/N-H cross-coupling/halogenation of β-thioalkyl-substituted α-alkenoyl ketene N,S-acetals occurred efficiently, affording 4-halo-5-thioalkyl-3-pyrrolones. Tunable C-S and C-halo bond transformations of the resultant pyrrolone derivatives led to highly functionalized N-heterocyclic compounds. [ABSTRACT FROM AUTHOR]

A new, efficient ionic liquid based synthetic procedure was developed for the preparation of highly substituted endocyclic enol lactones via the carbonylation coupling reactions of alkynes and 1,3-diketones in ionic liquid. The reactions proceeded in excellent regioselectivity and in reasonably good yields. The catalyst system can be recycled five times with only modest loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

(E/Z)-lsomers containing vinyl bromides were stereoselectively carbonylated to the corresponding (E)-α,β-ethylenic carboxylic acids in the ionic liquid [BMIM]PF6. Vinyl dibromides also underwent hydroxycarbonylation to give monoacids. The products are pure by proton NMR spectroscopic determination without purification by silica gel column chromatograghy or recrystallization. [ABSTRACT FROM AUTHOR]