The first example of the FBW rearrangement using of lanthanum metal and a catalytic amount of iodine was disclosed. When gem-diiodo- and gem-dibromoalkenes were treated with lanthanum metal in the presence of a catalytic amount of iodine, the reductive dehalogenation of these compounds smoothly proceeded to produce the corresponding alkynes in moderate to good yields.
gel-supported sodium hydrogen sulfate (NaHSO4/SiO2) or Amberlyst 15 as solid acid catalyst, and then the corresponding 3-acylisoxaszoles were obtained by reacting with alkynes via the 1,3-dipolar [3+2] cycloaddition. These heterogeneous catalysts are easily separable from the reaction mixture and reused. This synthetic method provides a facile, efficient, and reusable production of 3-acylisoxazoles.