Convenient synthesis of alkylhydrazides by the cobalt-catalyzed hydrohydrazination reaction of olefins and azodicarboxylates

Treatment of olefins 2 with 1.5 equiv of di-tert-butyl azodicarboxylate (3), 1 equiv of PhSiH3, and 1.5-5 mol % of the simple Co(III) catalyst 1 in ethanol at 23 degrees C affords the Markovnikov hydrazide product for a broad range of olefins in 62-94% yield.     

Convenient synthesis of dodeca-1,3-diynyl ketones by the “diacetylene zipper” reaction

Dodeca-1,3-diynyl ketones were synthesized by isomerization of dodeca-5,7-diyne with H₂N(CH₂)₂NHLi and treatment of the in situ prepared lithium derivative of dodeca-1,3-diyne with N-methoxy-N-methylcarboxamides. Dedicated to Corresponding Member of the Russian Academy of Sciences E. P. Serebryakov on the occasion of his 70th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 1017–1019, April, 2005.     

A novel procedure for the synthesis of multifunctional ketones through the Fukuyama coupling reaction employing dialkylzincs

Treatment of thiol esters 1 with dialkylzincs 2 in the presence of zinc bromide, that was in situ prepared from zinc dust and bromine, provided various functionalized ketones 3 in high yields. The reaction mechanism, which may shift the Schlenk equilibrium from dialkylzincs 2 to reactive alkylzinc bromide 5, was postulated to account for the facile coupling reaction.     

Convenient synthesis of 3,3,3-trifluoropropenyl compounds from aromatic aldehydes by means of the TBAF-mediated Horner reaction

A simple synthesis of 3,3,3-trifluoropropenyl compounds by means of the TBAF-mediated Horner reaction is described. The reagent, 2,2,2-trifluoroethyldiphenylphosphine oxide, was readily prepared either by Arbuzov reaction of ethyl diphenylphosphinite with 2,2,2-trifluoroethyl iodide or by treating chlorodiphenylphosphine with trifluoroacetic acid and water. Treatment of the phosphine oxide with aromatic aldehydes in the presence of TBAF at room temperature afforded the corresponding 3,3,3-trifluoropropenyl compounds in good yields. The present method is very convenient for preparing 3,3,3-trifluoropropenyl compounds from aromatic aldehydes in terms of availability of the reagent, operational simplicity, and good yields of the products.     

Convenient synthesis of selected meta- and ortho-substituted pentaarylpyridines via the Suzuki-Miyaura cross-coupling reaction

The first synthesis of sterically demanding, stable at room temperature atropisomeric derivatives of penta-(ortho-substituted phenyl)pyridines is described. The Suzuki-Miyaura cross-coupling reaction of pentabromopyridine and selected meta- and ortho-tolylboronic acids afforded a series of pentaarylpyridine derivatives. The structures of two room temperature stable atropisomeric derivatives of penta-(o-tolyl)pyridines were confirmed by single-crystal X-ray analysis. Racemic atropisomers were examined by ¹H NMR spectroscopy with a chiral solvating agent in order to visualize the presence of individual enantiomers.     

Convenient synthesis and reaction of various kinds of α-dehydroglutamic acid derivatives

Various conversions of methyl γ-methyl-α-(N-benzyloxycarbonyl)-α-dehydroglutarmate, derived by the condensation of methyl γ-methyl-α-oxoglutarate with benzyl carbamate, gave the corresponding five more different and interesting α-dehydroglutamic acid and a quasi-pyrodehydroglutamic acid derivatives.     

Convenient indole synthesis from 2-iodoanilines and terminal alkynes by the sequential Sonogashira reaction and the cyclization reaction promoted by tetrabutylammonium fluoride (TBAF)

The sequential Sonogashira reaction and the cyclization reaction of various 2-iodoanilines and terminal alkynes in the presence of a palladium catalyst and tetrabutylammonium fluoride (TBAF) gave the corresponding 2-substituted indoles in good yields.     

Convenient synthesis of porphine

Porphine formation from pyrrole and formaldehyde was examined in detail. Under optimized conditions, 9 mg of crystalline porphine was obtained per 1 ml of pyrrole.     

Synthesis of diaryl ketones via a phosphine-free Fukuyama reaction

The synthesis of unsymmetrical diaryl ketones via the Fukuyama coupling of thioesters and organozinc reagents is described. Typically, the synthesis of diaryl ketones using this methodology provides low yields. The simple complex, Pd(dba)(2), was found to convert a variety of aryl thioesters to diaryl ketones in good yields.     

Convenient synthesis of palladium nanoparticles and catalysis of Hiyama coupling reaction in water

An efficient synthesis of Pd nanoparticles in water has been developed using a Fischer carbene complex of tungsten as the reductant and PEG as the capping agent. The colloidal palladium (1 mol %) efficiently catalyzes Hiyama cross-coupling reactions performed in air. Excellent yields of products were obtained with a wide range of substrates. Catalytic activity and stability of the nanoparticles were found to be inversely correlated.     

A practical procedure for the synthesis of multifunctional aldehydes through the Fukuyama reduction and elucidation of the reaction site and mechanism

A highly efficient heterogeneous Pd/C catalyst D1 was found to effect the reduction of thiol esters 1 to the corresponding aldehydes 2 with such a low catalyst loading as 0.5-1.0 mol %. The chemical properties of the Pd/C catalysts together with the XRF analysis reveal that the reduction is most likely to proceed on the solid surface of the Pd/C catalyst rather than in the solution phase outside the pores. A reaction mechanism through oxidative addition of Pd to the thiol esters 1 was postulated by detection of the oxidative addition intermediate by React IR analysis. A practical purification of 2 was accomplished by conversion to water-soluble bisulfite adducts 7.     

Convenient synthesis of glycosyl bromide from 1-O-acetyl sugars by photo-irradiative phase-vanishing reaction of molecular bromine

The synthesis of glycosyl bromides from 1-O-acetyl sugars using a photo-irradiative phase-vanishing method involving molecular bromine was achieved. A bottom phase of molecular bromine was overlaid first with perfluorohexanes (FC-72), followed by overlaying with ethyl acetate containing a 1-O-acetyl sugar. Upon irradiation, the bromine layer gradually disappeared, leaving two phases. Glycosyl bromide was obtained in good yield from the ethyl acetate phase.     

Convenient synthesis of bisphosphonomethylphosphoric acid

The reaction of phosgene or triphosgene with trimethylsilyl dialkylphosphites led to bisdialkylphosphonomethyl‐dialkylphosphates in good yields. The cleavage of the allyl ester was carried out under mild conditions using the Wilkinson catalyst. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:111–113, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10105     

Camouflaged carborane amphiphiles: synthesis and self-assembly

A series of amphiphilic amine hydrochloride salts of B-polymethylated (camouflaged) (aminoalkyl)- and bis(aminoalkyl)carboranes have been designed and synthesized in high yield for the purpose of constructing novel carborane-based nanomaterials. Due to the distinct separation of the hydrophobic and hydrophilic regions within each salt, the mono- and disubstituted amphiphiles spontaneously self-assembled upon sonication into rod-shape micro/nanostructures in aqueous solutions. The effects of concentration, method of dispersion, solvent, chain length, counterion, ionic charge, and underlying carborane cage structure on the formation of the these rod products were investigated. The microrods have been studied by transmission electron microscopy (TEM), optical microscopy, X-ray powder diffraction (XRD), thermogravimetric/differential thermal analysis (TG/DTA), and FTIR. For the first time, this work clearly demonstrates the self-assembly of B-polymethylated carboranes into supramolecular structures.     

Convenient synthesis of functionalized terphenyls

A convenient synthetic methodology amenable for rapid synthesis of differentially functionalized terphenyls is described. Orthogonality requirements for the incorporation of phenoxy acetic acid and carboxamide function have been satisfied by utilization of hydroxyethoxy group as a precursor of the acid. Highly efficient and universal procedures have been developed for acid and amide formation.     

Convenient synthesis of 5-azacoumarins

2-Formyl-3-hydroxypyridine and its 6-methyl derivative have been condensed with ethoxycarbonylmethyl-enetriphenylphosphorane and alkyl derivatives to afford 5-azacoumarins substituted in the second case by an alkyl group at 3-position by two different ways according to the used phosphorane.     

Convenient synthesis of 7-hydroxyindole

7-Hydroxyindole, the key building block for the synthesis of AJ-9677 1, was prepared from indoline in six steps in 36% overall yield. AJ-9677 1 is a potent and selective adrenaline β3-agonist being considered as a clinical candidate to treat obesity in those who are suffering from diabetes.