a way to avoid using precious metals the application of highsurface activated carbon for the synthesis of isoindoles via the dielsalder reaction of 2hpyran2ones the application of activated carbon darco kb for the acceleration and direction of the transformation of various 2hpyran2ones with nsubstituted maleimides toward isoindole derivatives through the reaction sequence cycloadditioneliminationdehydrogenation is described in this reaction the catalyst mainly influences the dehydrogenation step which is essential to avoid the formation of bicyclo222octenes as the other possible products we found that the combination of darco kb as the metalfree catalyst and decalin as the solvent in a closed vessel represents the most successful conditions a comparison of the effect of various dehydrogenation catalysts and reaction conditions is also presented in addition we have proven that the aromatization occurs via a hydrogen transfer from the cyclohexadiene intermediate to the maleimide derivative therefore producing succinimides this transfer is facilitated by the active surface of the heterogeneous carbonbased catalyst