ABSTRACT
Although photoinduced electron transfer reactions occupy a central position in the chemistry of life [1] their application to organic synthesis started only a few decades ago [2]. At first glance this is somewhat surprising since analogous reactions via neutral radicals are already known for a long time [3]. The reason for this delayed development of photoinduced electron transfer (PET) reactions may be simply related to the role of photochemistry in chemistry in general. Although the beginnings of modern organic photochemistry were laid more than 100 years ago [4], the fundamental understanding of electron transfer in general [5] and of PET processes in particular [1] developed relatively late in the middle of the twentieth century. Therefore, many photochemical transformations that are initiated by electron transfer were originally thought to proceed via homolytic steps.
