Arylethylenes are known to undergo several types of dimerization processes under thermal or photochemical conditions to afford 1, 4-and 1, 6-cycloadducts as well as open-chain dimers. The relative amount obtained of each class of products depends both on the nature of the subtituents attached to the aryl groups and the reaction conditions. Photochemical dimerizations are usually promoted by sensitizers and proceed via intermediate radical ...
