Dehydrogenation/Diels-Alder Cycloaddition Domino Reaction of 9,10-Dihydroanthracene with N-Substituted Maleimides Triggered by the Application of Activated Carbon

The application of 9,10-dihydroanthracene in a sequence of dehydrogenation/Diels-Alder cycloaddition reactions with a variety of N-substituted maleimides is described. The in situ transformation of the 9,10-dihydroanthracene into the corresponding anthracene, which is acting as a diene, is accelerated by activated carbon (Darco® KB). The anthracene/maleimide cycloadducts thus obtained might offer some important biochemical applications. The role of the activated carbon in this domino reaction is to accelerate the elimination of hydrogen from the 9,10-dihydroanthracene. The starting maleimides (i.e., dienophiles) were shown to also act as the actual oxidants as they are transformed into the corresponding succinimides. However, the atmospheric oxygen, at least partially, also plays the role of oxidant.