1772-10-7Relevant academic research and scientific papers
Indium(III) triflate - A catalyst for greener aromatic alkylation reactions
Mack, Ryan,Askins, Grant,Lowry, Jacob,Hurley, Nathan,Reeves, Perry C.
, p. 1262 - 1265 (2014/01/06)
An environmentally friendly method for alkylating aromatic compounds with simple alcohols in the presence of a catalytic amount of indium(III) triflate is reported. Ionic liquids are used as solvents and energy-efficient heating is provided by microwave radiation. Good yields are obtained with benzyl, secondary, and tertiary alcohols. Simple primary alcohols are not effective alkylating agents under these conditions. With tertiary alcohols, activated aromatic compounds such as toluene and anisole must be used to obtain good yields. The catalyst, which is immobilized in a water-insoluble ionic liquid, can be easily recycled without significant loss of activity.
Probing gaseous ion-molecule complexes with chiral agents: The reaction of arenium ions with (R)-(-)-s-butyl chloride
Aschi,Cacace,Troiani
, p. 83 - 85 (2007/10/03)
Enantiomerically pure, gaseous reagents can be used to probe the chemical identity and the spatial arrangement of reaction partners confined within ion molecule complexes. The addition of gaseous arenium ions to (R)-(-)s-C4H9Cl affords complexes within which aromatic alkylation proceeds with complete racemization. This suggests that the components of the complex undergo mutual rotation and that the s-butyl cation is the electrophile.
Tin Radical Addition to Alkynyl Sulfides: Reactivity of the Intermediate Thioalkyl-Substituted β-(Tributylstannyl)vinyl Radicals
Capella, Laura,Montevecchi, Pier Carlo,Nanni, Daniele
, p. 3368 - 3374 (2007/10/02)
Phenyl and benzyl alkynyl sulfides 1a-g and 3a, phenylalkynylamines 19a,b, ethers 22a,b, and selenide 31 reacted with tributyltin radicals to give intermediate β-stannylvinyl radicals, whose fate depended on the nature of the side chain. 4-Phenylthio-substituted but-1-en-2-yl radicals underwent stereospecific 5-exo cyclization on the adjacent phenyl ring.The resulting spirocyclohexadienyl radicals gave thiophenes and thiopyrans by carbon-sulfur bond scission or ring expansion on the exocyclic double bond, respectively.Similar behavior was exhibited by the corresponding selenium-containing radical, which afforded a selenophene almost exclusively. (Benzylthio)alkyl-substituted radicals gave products deriving from intramolecular SH2 substitution at the sulfur atom, whereas propargyl sulfides yielded a stannylallene via a β-scission reaction.No 6(or more)-membered ring closure was observed with pentynyl and hexynyl phenyl sulfides 1b,c, which gave only the (E)-addition products of tin hydride; oxygen- and nitrogen-containing vinyl radicals also gave the (E)-adducts exclusively.An interaction between the unpaired electron orbital and the empty low-energy orbitals of the heteroatom might explain why sulfur and selenium can undergo 5-exo cyclization.
Alkylation of Nitriles with Gaseous Carbenium Ions. The Ritter Reaction in the Dilute Gas State
Cacace, Fulvio,Ciranni, Giovanna,Giacomello, Pierluigi
, p. 2258 - 2261 (2007/10/02)
Radiolytically formed carbenium ions, such as sec-C3H7+, sec-C4H9+, and t-C4H9+, react in the gas phase with model aliphatic and aromatic nitriles yielding the corresponding nitrilium ions.The latter undergo efficient condensation with water that eventually leads to the formation of the corresponding N-alkylamides.The mechanism is analogous to the Ritter reaction in solution.The reactivity and selectivity of the gas-phase electrophilic attack on nitriles has been deduced from competition experiments under conditions that largely exclude the effects of solvation, ion pairing, etc., which complicate the interpretation of solution-chemistry measurements.
LOW TEMPERATURE REACTION OF AROMATIC HYDROCARBONS WITH ETHYLENE AND SOLVATED ELECTRONS
Russey, William, E.,Haenel, Matthias, W.
, p. 4065 - 4068 (2007/10/02)
A wide variety of aromatic hydrocarbons can be ethylated at benzylic and aromatic positions by treatment with ethylene and potassium in glyme/octaglyme at -25 deg C.
Liquid Phase Alkylation of Toluene with n-Butene
Kulsrestha, Girendra N.,Shanker, Uma,Pathania, Bikram S.,Negi, Janaki,Bhattacharyya, Kshitindra K.
, p. 298 - 302 (2007/10/02)
Alkylation of toluene with n-butene to obtain s-butyltoluene (SBT) has been studied in the presence of AlCl3.The isomer distribution of the product is found to vary with catalyst concentration, reaction temperature and the contact period.Using 1.7 mol percent catalyst, butene conversion is > 95 percent at 32 deg C with a selectivity of 85 percent towards SBT formation.At low catalyst concentration and subzero temperatures, mainly o- and p-SBT are formed.Above 5 deg C, m- and p-isomers are predominant.The results indicate that initially formed o- and p-SBT isomerise mainly by an intermolecular mechanism to m-SBT, the isomerisation of former being faster, to finally attain an equilibrium composition of o-, 2-3 percent; m-, 71-72 percent and p-, 25-27 percent.H2SO4 and BF3-H3PO4 catalysts result mainly in o- and p-isomers.This variation in the isomer distribution is considered to be due to differences in the acidity of the catalysts.
Aromatic Substitution in the Gas Phase. Alkylation of Arenes by Gaseous C4H9+ Cations
Cacace, Fulvio,Ciranni, Giovanna,Giacomello, Pierluigi
, p. 1513 - 1516 (2007/10/02)
Butyl cations, obtained in the dilute gas state from the radiolysis of butane in the pressure range from 70 to 750 torr, have been allowed to react with benzene, toluene, and their mixtures or with trace amounts of o-xylene in the gaseous system.The gas-phase butylation yields invariably sec-butylarenes, remarkably free of isomeric byproducts, namely n- and tert-butylarenes.Other alkylation experiments, where gaseous butyl cations from the reaction of butane with radiolytically formed H3+ ions were used as reagent, confirmed the exclusive formation of sec-butylarenes.The butylation process displays the positional and substrate selectivity and the dependence of orientation on the pressure of the system, typical of other gas-phase ionic substitutions.At high pressures, ortho-para orientation predominates in the sec-butylation of toluene, with a ortho:meta:para ratio of 43:30:27 at 715 torr.As the pressure is reduced, a gradual shift in favor of the thermodynamically most stable meta-subsltituted arenium ion is observed, leading to a ortho:meta:para ratio of 31:48:21 at 70 torr.
