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A Ni-catalyzed reductive cyclization of 1,6-dienes affords 3,4-disubstituted cyclopentane and pyrrolidine derivatives with high trans diastereoselectivity. This cyclization reaction enables the efficient synthesis of trans-3,4-dimethyl gababutin, a pharma

A mild, practical, and environmentally friendly route to vinyl sulfones and sulfonamides has been developed based on the reaction of aliphatic amines with arenesulfonyl chlorides in the presence of eosin Y as a photocatalyst under visible light. The method permits the selective formation of vinyl sulfones or sulfonamides, depending on the oxidation environment and solvent. A wide range of products were obtained in moderate to good yields under the optimized conditions.

The positive ion electrospray mass spectra of a range of sulphonamides of general structure CH3C6H4SO2NHR1 [R1 = CnH2n+1 (n = 1-7), CnH2n-1 (n = 3, 4), C6H5, C6H5CH2 and C6H5CH(CH3)] and CH3C6H4SO2NR1R2 [R1, R2 = CnH2n+1 (n = 1-8)] are reported and discussed. The protonated sulphonamides derived from saturated primary and secondary aliphatic amines generally fragment to only a limited extent unless energised by collision. Two general fragmentations are observed: firstly, elimination of an alkene, CnH2n, obtained by hydrogen abstraction from one of the CnH2n+1 alkyl groups on nitrogen; secondly, cleavage to form CH3C6H4SO2+. The mechanism by which an alkene is lost has been probed by studying the variation of the intensity of the [M + H - CnH2n]+ signal with the structure of the alkyl substituent(s) on nitrogen and by monitoring the competition between the loss of different alkenes from protonated unsymmetrical sulphonamides in which two different alkyl groups are attached to nitrogen. This fragmentation is favoured by branching of the alkyl group at the carbon atom directly attached to nitrogen, thus suggesting that it involves a mechanism in which the stability of the cation obtained by stretching the bond connecting the nitrogen atom to the alkyl group is critical. This interpretation also explains the competition between alkene elimination and cleavage to form CH3C6H4SO2+ (and, in some cases, cleavage to form C6H5CH2+ or [C6H5CHCH3]+).

Highly basic MgO nanoparticles with different sizes have been successfully immobilized over mesoporous carbon with different pore diameters by a simple wet-impregnation method. The prepared catalysts have been characterized by various sophisticated techniques, such as XRD, nitrogen adsorption, electron energy loss spectroscopy, high-resolution TEM, X-ray photoelectron spectroscopy, and the temperature-programmed desorption of CO2. XRD results reveal that the mesostructure of the support is retained even after the huge loading of MgO nanoparticles inside the mesochannels of the support. It is also demonstrated that the particle size and dispersion of the MgO nanoparticles on the support can be finely controlled by the simple adjustment of the textural parameters of the supports. Among the support materials studied, mesoporous carbon with the largest pore diameter and large pore volume offered highly crystalline small-size cubic-phase MgO nanoparticles with a high dispersion. The basicity of the MgO-supported mesoporous carbons can also be controlled by simply changing the loading of the MgO and the pore diameter of the support. These materials have been employed as heterogeneous catalysts for the first time in the selective synthesis of sulfinamides. Among the catalysts investigated, the support with the large pore diameter and high loading of MgO showed the highest activity with an excellent yield of sulfinamides. The catalyst also showed much higher activity than the pristine MgO nanoparticles. The effects of the reaction parameters, including the solvents and reaction temperature, and textural parameters of the supports in the activity of the catalyst have also been demonstrated. Most importantly, the catalyst was found to be highly stable, showing excellent activity even after the third cycle of reaction. Reuse and recycle: Highly basic MgO-functionalized mesoporous carbon with different pore diameters has been prepared (see picture). The material showed a much higher performance in the synthesis of sulfinamides than pure MgO nanoparticles. The catalyst was also highly stable and could be reused several times without affecting its activity. Copyright

A versatile method for fast scavenging a variety of electrophiles using carbon nanotubes functionalized by amino groups (CNT-NH2) is reported. Following the scavenging event, CNT-NH2 can be easily separated from the reaction mixture by filtration, leaving the desired products in excellent yields and purities.

(Chemical Equation Presented) The bis(imino)pyridine iron dinitrogen complex (iPrPDI)Fe(N2)2 catalyzes the hydrogen-mediated reductive cyclization of enynes and diynes with turnover frequencies comparable to those of established precious metal catalysts. Amino, oxygenated, and carbon-based substrates are readily cyclized to the corresponding hetero- and carbocycles with 5 mol % iron and 4 atm H2 at 23°C. Stoichiometric reactions between selected substrates and the iron compound under a N2 atmosphere established transfer dehydrogenation from an isopropyl aryl substituent to either the enyne or diyne substrate. In situ monitoring of the catalytic reaction by 1H NMR spectroscopy coupled with deuterium labeling experiments established rapid cyclization followed by turnoverlimiting hydrogenation. Copyright

A convenient, mild and efficient one-pot synthesis of new sulfonamides is described. The reaction of primary or secondary amine derived sulfonate salts in the presence of cyanuric chloride, triethylamine as base, and anhydrous acetonitrile as solvent at room temperature gives the corresponding sulfonamides in good to excellent yields. Georg Thieme Verlag Stuttgart.

The nucleophilic reactivity of amines of the norbornane, norbornene, and adamantane series toward p-toluenesulfonyl chloride and diphenyl chlorophosphate in acetonitrile at 25°C is determined mainly by the steric factor. Parameters characterizing spatial accessibility of the reaction center in the amine molecule have been determined. Cage-like substituents show no appreciable effect on the amine reactivity, as compared to common alkyl groups.

The reaction of different protected alcohols, amines and amides with lithium and a catalytic amount of naphthalene (4 mol %) in THF at low temperature leads to their deprotection under very mild reaction conditions, the process being in many cases chemoselective.

The kinetics of closure of N-tosylazacycloalkanes from the anions derived from N-tosyl-ω-bromoalkylamines have been investigated in 99percent aqueous Me2SO.Rate constants and effective molarities (EM) have now been obtained for the ring sizes 8-13, 17, an

The leaving group effect (kBr/kCl) has been determined for two typical series of SN2 cyclisation reactions in the ring size range of 3 to 6 in order to probe the effect of ring strain on transition state structure.The general increase of the magnitude of the leaving group effect on going from the less strained to the more strained ring systems indicates that bond making and bond breaking is significant also in the small ring transition states.The apparent unimportance of strain in the products to the ease of closure of the smallest rings is tentatively explained by the hypothesis that the adverse effect of ring strain is partially offset by a significant reduction of non-bonded interactions in the transition states.

Rates of cyclisation of a series of anions derived from N-tosyl-ω-bromoalkylamines to nitrogen heterocycles with three to seven members in Me2SO-H2O (99:1) have been studied.Rates vary markedly with ring size in the order 5 > 3 > 6 > 7 ca. 4.First order rate constants for cyclisation have been translated into effective molarities (EM) with reference to an appropriate intermolecular model reaction.Comparison of the present results with available literature data on SN2 ring-closure reactions leading to small- and common-sized rings reveals that the ease of formation of three-membered rings is much more structure-dependent than that of the higher homologues.This remarkable behaviour is believed to parallel the unique way in which the stability of three-membered rings is affected by structure.As a rule, the ease of cyclisation appears to bear an inverted relationship to the assumed strain energy of the ring product.The apparent opposition of this rule to earlier conclusions in the literature is discussed.

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