Reduction initiated domino reactions sequence

During the past few years, increasing numbers of reports have been published on the subject of domino reactions initiated by oxidation or reduction processes. This was in stark contrast to the period before our first comprehensive review of this topic was published in 1993 [1], when the use of this type of transformation was indeed rare. The benefits of employing oxidation or reduction processes in domino sequences are clear, as they offer easy access to reactive functionalities such as nucleophiles (e. g., alcohols and amines) or electrophiles (e. g., aldehydes or ketones), with their ability to participate in further reactions. For that reason, apart from combinations with photochemically induced, transition metal-catalyzed and enzymatically induced processes, all other possible constellations have been embedded in the concept of domino synthesis. 

In this chapter, we presented the importance of oxidation and reduction reactions as part of a domino process in organic synthesis. Particularly, in the synthesis of complex organic molecules, this allows for short, simple, economical, as well as highly selective approaches in which several bonds are formed in one process. Domino reactions initiated by oxidation or reduction reactions have seen enormous growth in the last years. However, the protocols dealing with domino reactions having an oxidation or a reduction in the middle of a reaction sequence or as the terminating step are yet to be explored to their full potential. 

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