Isomerization of 3-vinyl- and 3-ethynyl-o-carboranes to 2- and 4-vinyl and 2- and 4-ethynyl-m-carboranes

1. The isomerization of the 3-ethynyl- and 3-vinyl-o-carboranes in the gas phase leads to the respective formation of mixtures of the 2- and 4-ethynyl-m-carboranes and the 2- vinyl-m-carboranes. 2. The B-alkenyl-o- and B-alkenyl-m-carboranes enter into the electrophilic addition reaction more easily than the 1-alkenyl-o- and 1-alkenyl-m-carboranes.