931-09-9Relevant articles and documents
Reactivity of bismuth(III) halides towards alcohols. A tentative to mechanistic investigation
Keramane, El Mehdi,Boyer, Bernard,Roque, Jean-Pierre
, p. 1909 - 1916 (2001)
The reactivity of bismuth(III) halides (BiX3; X=Cl, Br and I) towards a series of alcohols has been investigated. Three different reactions have been studied, namely: halogenation, dehydration and etherification. The behaviour of these bismuth derivatives was found to depend on the nature of the halide bonded to the bismuth atom. Their reactivities can be interpreted on the basis of the Hard and Soft Acids and Bases (HSAB) principle. A mechanism is proposed which involves the formation of a complex of the alcohol with Bi(III).
Stereoretentive chlorination of cyclic alcohols catalyzed by titanium(IV) tetrachloride: Evidence for a front side attack mechanism
Mondal, Deboprosad,Li, Song Ye,Bellucci, Luca,Laino, Teodoro,Tafi, Andrea,Guccione, Salvatore,Lepore, Salvatore D.
, p. 2118 - 2127 (2013/04/10)
A mild chlorination reaction of alcohols was developed using the classical thionyl chloride reagent but with added catalytic titanium(IV) chloride. These reactions proceeded rapidly to afford chlorination products in excellent yields and with preference for retention of configuration. Stereoselectivities were high for a variety of chiral cyclic secondary substrates including sterically hindered systems. Chlorosulfites were first generated in situ and converted to alkyl chlorides by the action of titanium tetrachloride which is thought to chelate the chlorosulfite leaving group and deliver the halogen nucleophile from the front face. To better understand this novel reaction pathway, an ab initio study was undertaken at the DFT level of theory using two different computational approaches. This computational evidence suggests that while the reaction proceeds through a carbocation intermediate, this charged species likely retains pyramidal geometry existing as a conformational isomer stabilized through hyperconjugation (hyperconjomers). These carbocations are then essentially "frozen" in their original configurations at the time of nucleophilic capture.
The Interaction of Arenesulphonyl Chlorides, Aluminium Chloride, and Saturated Alicyclic Hydrocarbons containing at least One Tertiary Hydrogen Atom
Ewedemi, Rotimi O.,Fields, Roy,Holt, Geoffrey
, p. 1466 - 1500 (2007/10/02)
Cycloalkanes having at least one tertiary hydrogen react with a mixture of benzenesulphonyl chloride and aluminium chloride in carbon disulphide, with reactivity decreasing in the order cis-decalin ca. cis-hexahydroindane > trans-decalin >/= dicyclohexyl > methylcyclohexane > t-butylcyclohexane > methylcyclopentane.Although hydrogen chloride was evolved and benzenesulphonyl chloride was reduced to benzenesulphinic acid in all the reactions, only cis-decalin, and, to a much smaller extent, dicyclohexyl, gave appreciable amounts of chloro- or dichloro-cycloalkanes.In other reactions the major products were hydrocarbon "dimers" and "trimers" apparently formed by attack by the carbenium ion on cycloalkenes formed in the reaction.Electron-attracting substituents in the arenesulphonyl chloride enhanced the rate of reaction with cis-decalin, and electron-donor substituents retarded the reaction, which appears to proceed via hydride-ion abstraction by the arenesulphonyl halide-aluminium halide "oxonium complex" rather than by the (+) ion.