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A boron trihalide mediated alkyne-aldehyde coupling reaction leading to stereodefined 1,3,5-triaryl-l,5- dihalo-1,4-pentadienes is described. The study led to the discovery of a direct substitution of hydroxyl groups by stereodefined alkenyl moieties using alkenylboron dihalides. During the investigation, it was also discovered that, at low temperatures, the reaction of BCI3 with alkynes produces monovinylboron dichioride rather than the reported divinylboron chloride. A modified reaction mechanism for the boron trichloride mediated alkyne-aldehyde coupling reaction is now proposed. The reaction temperature and mode of addition have been found to have dramatic affects on the stereochemistry of the diene products. [ABSTRACT FROM AUTHOR]

Tuberoside M ( 1 ), isolated from the seeds of Allium tuberosum , shows a significant inhibitory effect on the growth of the human promyelocytic leukemia cell line (HL-60) with IC 50 value of 6.8 μg/ml. On the basis of spectral data and chemical reaction, its structure was established as (25 S )-5β-spirostane-1β,3β-diol 3- O -α- l -rhamnopyranosyl-(1→4)-β- d -glucopyranoside. [ABSTRACT FROM AUTHOR]

A combinative iron(III) chloride/sodium iodide system was found to be very efficient for the iododemetallation of both organotrifluoroborates and tributyl(aryl)stannanes. A variety of functional groups tolerate the mild reaction conditions. [ABSTRACT FROM AUTHOR]

Abstract: In the presence of iron trichloride, the hydrolysis of potassium organotrifluoroborates occurs smoothly at room temperature to afford the corresponding organoboronic acids in good to excellent yields. The hydrolysis is effective for aryltrifluoroborates as well as alkenyl- and alkyl-trifluoroborates. [Copyright &y& Elsevier]

The article analyzes the stabilities of benzylic, allylic, and propargylic cabocations. These cations from alkoxides are well-documented and have been the subject of several theoretical and experimental studies. However, due to the strong acidic conditions required, the availability of these cations has not resulted in their general use as synthetic intermediates.

A novel iron-catalyzed intermolecular decarboxylative Csp3−Csp2coupling reaction using proline derivatives as starting materials is developed. In this process, a series of potentially useful ligands (tertiary aminonaphthol) for catalysis was obtained. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed tandem C--H activation/biscyclization reaction of propargylic carbonates with terminal alkynes was determined, which allowed the tetracyclic benz[a]anthracene framework to be constructed with high regioselectivity. A possible mechanism for this tandem C--H activation/biscyclization process was discussed. [ABSTRACT FROM AUTHOR]

A novel method for the construction of 2,3-dihydro-5-iodopyran-4-one through a domino cyclization/migration reaction of 1-alkynyl-2,3-epoxy alcohol was developed. Wet solvent is essential for this reaction. The resulting iodine- containing product can be readily elaborated to more complex products by using known organopalladium chemistry. [ABSTRACT FROM AUTHOR]

A palladium-catalyzedaryldifluoroalkylation of alkynes with ethyl difluoroiodoacetate andarylboronic acids as reaction partners is described. The alkyne difunctionalizationprocess provides various aryldifluoroalkylated products in one potunder mild reaction conditions. A wide range of alkynes and diversearylboronic acids are compatible with these reaction conditions. Highreaction efficiency and broad substrate scope are the notable featuresof this transformation. Preliminary mechanistic investigations indicatethat a difluoroalkyl radical addition pathway is involved in thistransformation. [ABSTRACT FROM AUTHOR]

A novel BF3⋅Et2O-promoted tandem reaction of easily prepared 2-propynolphenols/anilines and trimethylsilyl azide is developed to give C2-alkenylated benzoxazoles and benzimidazoles in moderate to good yields. Most reactions could be accomplished in 30 min at room temperature. This tandem process involves a Csp-Csp2 bond cleavage and a C-N bond formation. Moreover, both tertiary and secondary propargylic alcohols with diverse functional groups were tolerated under the mild conditions. [ABSTRACT FROM AUTHOR]

Brensted acid catalyzed tandem cyclization was found to be highly effective for the preparation of a series of polysubstituted 4-pyrones from diynones (yield up to 99%). 4-Pyridone and 3-pyrrolone derivatives were also selectively synthesized by employing NTS and/or Bransted acid. NIS as an electrophilic reagent could promote these reactions efficiently and rapidly under very mild reaction conditions [ABSTRACT FROM AUTHOR]

The high-spin level structure of 186Au is re-investigated by means of in-beam j-ray spectroscopy via the 172Yb(19F, 5nj)186Au reaction. The oblate bands previously reported are revised and extended to higher-spin states. A new Iπ = (20+) excited state has been identified and assigned to the πh-11/2 ® configuration. The total Routhian surface and cranked shell model calculations suggest that the πhg11/2 ® v&ggr;gg322/2hgg/'2 band in 186Au has a non-axial deformation. [ABSTRACT FROM AUTHOR]

Activation of C2 and C3 of indoles by molecular iodine (I2) and base followed by in situ reaction with 1-(2-tosylaminophenyl)ketones or 2-tosylaminobenzaldehyde can afford highly substituted indolo(23-b)quinolines in moderate to excellent yields (up to 99%). The reaction provides a metal-free selective difunctionalization of indoles. The synthetic potential of the protocol has been illustrated by die synthesis of neocryptolepine and its 11-methyl analogue. [ABSTRACT FROM AUTHOR]

A palladium-/copper-catalyzed intermolecular C–H amination reaction of indoles has been developed. This reaction proceeds in good to excellent yields to produce a variety of 2-amino-substituted indoles and exhibits excellent regioselectivity at room temperature. Furthermore, chloroamination of indoles provides a simple method for the construction of C–N and C–Cl bonds in one step. [ABSTRACT FROM AUTHOR]

Highly substituted 3-iodoquinolines bearing different alkyl and aryl moieties can be synthesized in moderate to excellent yields (up to 99%) by 6-endo-dig iodocyclization of 2-tosylaminophenylprop-1-yn-3-ols with molecular iodine (I2) under mild conditions. The cyclization is highly regioselective and the resulting 3-iodoquinolines can be further functionalized by various coupling reactions. [ABSTRACT FROM AUTHOR]

The synthesis of 3-(aminoalkyl)coumarins starting with a platinum/scandium-cocatalyzed oxidative dehydrogenation of α,β-C(sp3)-H bonds of tertiary amines in the presence of ambient oxygen followed by reactions with substituted salicylaldehydes is revealed. The in situ formed enamines reacted with various salicylaldehydes, which resulted in the development of a one-pot synthetic protocol involving aldol reaction, cyclization, and then ring-opening. [ABSTRACT FROM AUTHOR]

A novel and convenient Pd(0)-catalyzed carboannulation with propargylic compounds for the synthesis of highly substituted aromatic amine derivatives in a one-pot operation was developed. In this process, a significant breakthrough in aminobenzannulation is observed. Moreover, the reaction appears to be very general and suitable for a variety of amines. [ABSTRACT FROM AUTHOR]

A mild and direct process for C−C bond formation from propargylic alcohols and olefin has been developed in the presence of a silver catalyst. In this reaction, trace amounts of water were necessary and allene alcohols 2 and 1,3-dienes 3 were obtained selectively. [ABSTRACT FROM AUTHOR]

We have disclosed a very nice advance of nickel(II)-catalyzed carboannulation reactions. Highly substituted indene derivatives are readily prepared in moderate to excellent yields under very mild reaction conditions in air via a nickel(II)-catalyzed cyclization of propargylic compounds with soft nucleophiles. [ABSTRACT FROM AUTHOR]

A facile and efficient synthesis of 1,3-diaryl-5-spirohexahy- dropyrimidines via a one-pot condensation of anilines, formaldehyde, and cyclohexanones is reported. In this one- pot, three-component reaction, six molecules of reactants are involved and six new covalent bonds are generated. Bicyclic products are obtained from the starting materials in one pot using readily available starting materials and catalysts. [ABSTRACT FROM AUTHOR]

A new three-component cyclization—coupling reaction catalyzed by palladium was developed, producing polysubstituted furans in good yields from readily available substrates. The reaction conditions and the scope of the process were examined, and a possible mechanism is proposed. [ABSTRACT FROM AUTHOR]

A direct nitration of aromatic sulfonamides using sodium nitrite as the nitrating agent has been developed. The reaction shows typically mono-substitution selectivity and can be enlarged to the gram scale with good yield. [ABSTRACT FROM AUTHOR]

The title compound, C17H16O4, was synthesized by the reaction of 2,3-dimethoxy­benzaldehyde and 2-hydroxy­acetophenone in 20% NaOH solution for 2 h, followed by crystallization from eth­yl acetate. The pyrone ring adopts a chair conformation. [ABSTRACT FROM AUTHOR]