Aryl triflates were transformed to aryl bromides/iodides simply by treating them with LiBr/NaI and [Cp*Ru(MeCN)(3)]OTf. The ruthenium complex also catalyzed the transformation of alkenyl sulfonates and phosphates to alkenyl halides under mild conditions. Aryl and alkenyl triflates undergo oxidative addition to a ruthenium(II) complex to form eta(1)-arylruthenium and 1-ruthenacyclopropene intermediates, respectively, which are transformed to the corresponding halides.
Bromide assisted addition of hydrogen bromide to alkynes and allenes
作者:Hilton M. Weiss、Kim M. Touchette
DOI:10.1039/a703569a
日期:——
The addition of 0.1 M quaternary ammonium bromide to a solution of 20% trifluoroacetic acid in methylene chloride causes a large rate increase in the reaction of non-conjugated alkynes. The initial vinyl bromide product reacts further to provide a mixture of isomeric vinyl bromides and dibromides. At high salt concentrations however, the secondary reactions are prevented and only the initial vinyl