1476-05-7Relevant academic research and scientific papers
Reactivity of bismuth(III) halides towards alcohols. A tentative to mechanistic investigation
Keramane, El Mehdi,Boyer, Bernard,Roque, Jean-Pierre
, p. 1909 - 1916 (2007/10/03)
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).
1,2- and 1,5-Stereocontrols in 5-Hexenyl Radical Cyclizations: Cooperative or Antagonist Effect. Conformation Experimental Results with MM2 Calculations of Transition States
Bertrand, M. P.,Riggi, I. De,Lesueur, C.,Gastaldi, S.,Nouguier, R.,et al.
, p. 6040 - 6045 (2007/10/03)
The cyclofunctionalization of 1,6-dienes 1 and 2 via the addition of tosyl radical allows the analysis of the combined effects of 1,2- and 1,5-stereocontrols on the outcome of 5-hexenyl radical cyclizations.MM2 calculations of the transition states agree quite well with the experimental selectivity, i.e., exclusive 1,2-trans control, and predominance of 1,5-cis over 1,5-trans relationship.The addition of TsBr to carbohydrate-derived epimeric dienes 3a and 3b shows that the stereochemistry of the newly formed C-C bond is controlled by the configuration of the C2 center of the radical. 1,5-trans or 1,5-cis selectivity can be achieved depending on the configuration of C2.
