Perfluoroorganosilver(I) compounds

A survey of different methods to prepare perfluoroorganosilver(I) compounds is given. The reaction of silver(I) fluoride with trimethyl(perfluoroorgano)silanes offers a new convenient method for the syntheses of these compounds. The formation of bis(perfluoroorgano)argentates(I) is discussed and the crystal structure of [PNP][Ag(CF₃)Cl] is described. Many examples of the application of perfluoroorganosilver(I) compounds as excellent synthons in nucleophilic substitutions and oxidative perfluoroorganylations are given.     

Reaction of diarylzinc compounds with copper(I) salts. Synthesis and characterization of arylcopper(I) compounds

The reaction of diarylzinc compounds with copper(I) salts is an excellent way of preparing stable arylcopper compounds in quantitative yields. These compounds have been characterized by IR, and by ¹H and ¹³C NMR spectroscopy. Cryoscopic molecular weight determinations show phenylcopper to be polymeric and 2-methylphenylcopper and 2,6-dimethylphenylcopper to be tetrameric in benzene. The compounds are believed to contain aryl groups bridging two copper atoms. Evidence is presented for rotation of these aryl groups around the C(1)—C(4) axis.     

Mono-organotin(IV) compounds as esterification and transesterification catalysts

A series of monoorganotin(IV) compounds has been investigated as transesterification catalysts for the reaction of butyl propionate with methanol. The most active catalysts were found to be those which contain tin-halogen bonds, e.g. monobutyltin trichloride (BuSnCl₃), and the least effective were the coordinatively saturated monoorganotin derivatives. Certain of the mono(2-carboalkoxyethyl)tin compounds were found to undergo a facile autocatalysed transesterification reaction with alcohols. Coordination of the carbonyl group in the ester to the tin catalyst is an important factor influencing its activity. A study of the catalysis of the esterification of propionic acid by BuSnCl₃ is reported.     

Reduction of Cr(VI) in presence of some amino compounds

The rate of reduction of Cr(VI) to Cr(III) in 0.05 M K2Cr2O7 has been studied and was found to be first order. The rate of reaction was measured in the absence of amino compounds and in the presence of o-nitroaniline, p-nitroaniline, m-toulidine, p-chloroaniline, and o-bromoaniline at four different temperatures. The rate of reaction was found to decrease with the addition of amines. Thermodynamic parameters DeltaG*, DeltaH*, and DeltaS* were calculated from the study.     

Geminal (difluoroamino)nitro compounds

A novel preparative method for the synthesis of geminal (difluoroamino)nitro compounds was developed, The method involves the reaction ofN,N-difluoro-O-fluorosulfonyl- hydroxylamine with the corresponding salts of nitro compounds, Dependences of the yields of (difluoroamino)nitro compounds on the reaction conditions, the nature of the cation in the salts, and the properties of solvents were studied.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11. pp. 2689–2692, November, 1996.     

Reactions of 1,2-bis(trifluoroacetyl)benzene with nucleophiles leading to heterocyclic compounds

The reaction of 1,2-bis(trifluoroacetyl)benzene (II) with ammonia, hydrazine, hydroxylamine and L-alanine has been investigated and the resulting heterocyclic compounds fully characterized on the basis of spectral data. The reaction of II with $\text{o}$-aminophenol and $\text{o}$-phenylenediamine led to the formation of tetracyclic compounds XI and XII respectively. The structure of compound XII has been further supported by single crystal X-ray crystallography. Our studies reveal the potential of the diketone II as a valuable synthon for the synthesis of a variety of heterocyclic systems with trifluoromethyl substituents.     

Synthesis of P(O)-S organophosphorus compounds by dehydrogenative coupling reaction of P(O)H compounds with aryl thiols in the presence of base and air

The synthesis method of P(O)-S organophosphorus compounds by dehydrogenative coupling reaction of P(O)H compounds and aryl thiols was developed. The reaction was carried in the presence of a base and air, and exhibited good characters such as metal-free, mild reaction temperature, excellent substrate tolerance and with moderate to good yields. A plausible mechanism was proposed.     

New qualitative colour reaction for the identification of copper(I) compounds and complexes

The colour reaction of copper(I) salts and complexes, in sulphuric acid medium, with ferricyanide and ammonia, has been used for the general identification of cuprous compounds. A sulphuric acid solution of Cu(I) compound, when treated with a dilute ferricyanide solution in the presence of ammonia, gives a salmon-pink, red-pink, pink-purple or purple colour or precipitate, characteristic of copper(I). Copper(II) compounds fail to give a positive response. The reaction also forms the basis of a test for ammonium ion and differentiation between ferrocyanide and ferricyanide. The preparation of the copper(I) complex of 1-allyl-2-tetrazoline-5-thione is described.     

The structures of some (hexamethyl-1,5,9,13-tetraazacyclohexadecadiene)copper(II) compounds

The structure of the crystalline azamacrocyclic product formed by reaction of bis(propane-1,3-diamine)copper(II) perchlorate with acetone has been determined as N-rac-(6,8,8,14,16,16-hexamethyl-1,5,9,13-tetraazacyclohexadeca-5,13-diene)copper(II) · N-meso-(6,8,8,14,14,16-hexamethyl-1,5,9,13-tetraazacyclohexadeca-5,16(1)-diene)copper(II) perchlorate, with the cis, 5,16(1)-diene, and trans, 5,13-diene, isomeric cations co-crystallised. The structures of three compounds crystallised from solutions of this mixture have been determined. N-rac-(6,8,8,14,14,16-hexamethyl-1,5,9,13-tetraazacyclohexadeca-5,16(1)-diene)copper(II) tetrachlorozincate has an irregular flattened tetrahedral coordination geometry with trans-N-Cu-N angles of 139.27(8)° and 155.94(8)°. (Hexamethyl-1,5,9,13-tetraazacyclohexadecadiene)(thiocyanato-N)copper(II) perchlorate has twofold symmetrical square-pyramidal cations. A (μ-cyano)-tetracyanonickelate(II) compound has two (hexamethyl-1,5,9,13-tetraazacyclohexadecadiene)copper(II) cations each with a single axially coordinated tetracyanonickelate(II) group. The compounds, except for the tetrachlorozincate(II) salt, show disorder in the location of the imine functions and axial methyl substituents, attributed to co-crystallisation of enantiomers for the N-rac-trans isomer and/or of rotated arrangements of the N-meso-cis isomer. For the thiocyanato and tetracyanonickelato compounds this disorder precluded unambiguous assignment of configuration.     

Applications of bismuth(III) compounds in organic synthesis

This review article summarizes the applications of bismuth(III) compounds in organic synthesis since 2002. Although there are an increasing number of reports on applications of bismuth(III) salts in polymerization reactions, and their importance is acknowledged, they are not included in this review. This review is largely organized by the reaction type although some reactions can clearly be placed in multiple sections. While every effort has been made to include all relevant reports in this field, any omission is inadvertent and we apologize in advance for the same (358 references).     

Thermal decompostion of dicyclopentadienyltitanium(IV) diaryl and dibenzyl compounds

The thermal decomposition of compounds of the type Cp₂TiR₂ (Cp = cyclopentadienyl, R = aryl or benzyl) in the solid state and in various solvents has been studied. In the solid state and in aromatic and aliphatic hydrocarbon solvents the compounds decompose with quantitative formation of RH and a Ti-containing residue which has lost the Cp₂Ti structure. Experiments with deuterated compounds and solvents showed that decomposition proceeds via intramolecular abstraction of a hydrogen atom either from a cyclopentadienyl ring or from the other coordinated group R. Results of insertion reactions with tolane confirm these two reaction pathways. In tetrahydrofuran and tetrachloromethane, decomposition proceeds in a more complex way, with participation of the solvent.     

Manganese(III)-mediated oxidative annulation of vinylidenecyclopropanes with 1,3-dicarbonyl compounds

Manganese(III)-mediated oxidative annulation of vinylidenecyclopropanes with 1,3-dicarbonyl compounds in acetonitrile/acetic acid produces the corresponding functionalized dihydrofuran derivatives in moderate to good yields under mild conditions. The substrate scope has been examined and a plausible reaction mechanism has been also proposed on the basis of experimental results and previous literature.     

The reaction of diarylzinc compounds with silver salts : Synthesis and characterization of arylsilver(I) compounds

The reaction of diarylzinc compounds with silver(I) salts is an excellent method of preparing stable arylsilver compounds in quantitative yields. These compounds have been characterized by IR and ¹H and ¹³C NMR spectroscopy Cryoscopy in benzene shows phenylsilver to be polymeric, and the methyl-substituted phenylsilver compounds to be trimers. All the compounds appear to be associated via aryl groups bridging between two silver atoms. As in the case of the corresponding copper compounds, the data point to the existence of rotation of these aryl groups around the C¹C⁴ axis. C¹C⁴ axis.     

Ni(II)-catalyzed Conia-ene reaction of 1,3-dicarbonyl compounds with alkynes

[reaction: see text]. We have discovered a Ni(II)-catalyzed Conia-ene reaction of 1,3-dicarbonyl compounds with alkynes. In the presence of Ni(acac)2 and Yb(OTf)3, various acetylenic 1,3-dicarbonyl compounds underwent Conia-ene reaction to give mono- and bicyclic olefinic cyclopentanes. A mechanism involving the enol-yne-Ni complex formation is proposed and supported by deuterium-labeling experiments.     

Melt polymerization of hexachlorocyclotriphosphazene in the presence of organotin (IV) compounds

The melt polymerization of hexachlorocyclotriphosphazene to poly(dichlorophosphazene) has been studied in the presence of organotin (IV) compounds. Unlike other typical Lewis acids, diethyltin (IV) chloride, Et₂SnCl₂, has shown to be an inhibitor for the thermal polymerization of the trimer, raising the activation energy to 70 kcal/mol. Diethyltin(IV) chloride remarkably delayed the rate of polymerization and efficiently inhibited the crosslinking reaction, thus leading to an improvement in the yield of the linear polymer without sacrifice to its molecular weight. © 1993 John Wiley & Sons, Inc.     

Ti(IV)-catalyzed asymmetric sulfenylation of 1,3-dicarbonyl compounds

The electrophilic enantioselective sulfenylation of 1,3-dicarbonyl compounds with phenylsulfenyl chloride is effectively catalyzed by [Ti(TADDOLato)] complexes. The corresponding products are obtained in moderate to high yields. The highest ee values (up to 97 %) are obtained in toluene at room temperature and with a typical catalyst loading of 5 mol %. Bulky ester groups and sterically undemanding substituents at the alpha-position were found to be crucial structural features of the starting materials in order to assure high enantioselectivity. The absolute configuration of one of the chiral products has been determined. The stereochemical course of the reaction is similar to that of analogous [Ti(TADDOLato)]-catalyzed atom-transfer reactions. A common side-reaction the sulfenylated products undergo is a deacylation leading to racemic alpha-sulfenylated esters.     

The synthesis of 2-(2-furyl) 1,3-dicarbonyl compounds

2-furyl derivatives are easily synthesised by intermolecular condensation of 2,5-dihydro-2,5-dimethoxy furan (DHDMF) with active methylene compounds by a simple and cheap procedure. The reaction applies only to 1,3-dicarbonyl compounds and a general mechanism is proposed.     

Interaction of nitrogen-containing propargyl compounds with CH-acids in the presence of mercury(II) acetate

Regiochemistry of the reaction of nitrogen-containing propargyl compounds with CH-acids in the presence of mercury(II) acetate has been studied. The possibility of alkylation at the substituted carbon atom of the triple bond of the nitrogen-containing propargyl compounds by sodium salts of acetylacetone and acetoacetic ester with the formation of prototropic isomers has been shown.     

Gas-chromatographic determination of organomercury(II) compounds

Gas chromatography has proved to be an invaluable technique not only for the identification and determination of organomercury(II) compounds but also for differentiating inorganically bound from organically bound mercury. It also offers a possible route for determining various inorganic species through their conversion into organomercury(II) compounds. These procedures and the chemical and instrumental problems associated with them are reviewed.     

Recent advances in transition-metal-catalyzed asymmetric reactions of diazo compounds with electron-rich (hetero-) arenes

The transition-metal-catalyzed reaction of diazo compounds with arenes or heteroarenes is an efficient and straightforward approach to functionalize aromatic compounds. This digest summarizes recent progresses on transition-metal-catalyzed asymmetric reactions of diazo compounds with electron-rich (hetero-) arenes, including C–H functionalization, cascade reaction, cyclopropanation, cycloaddition, Buchner reaction and intramolecular dearomatization.