4. Sequential radical multicomponent reactions

In this article, we have also included two recently-developed types of reaction which are grouped together here under the heading of "sequential reactions". These processes are multicomponent and necessarily include a radical chemistry step. We have distinguished between radical multicomponent reactions followed by a transformation that may be radical, ionic or organometallic, and non-radical multicomponent reactions (Ugi, Passerini) terminated by a radical process. These sequential processes (the various components are not added at the same time at the start of the reaction) thus contribute to increasing molecular complexity in a single operation, and significantly extend the scope of conventional multicomponent reactions. These few examples also point to a wide range of prospects for building new carbon skeletons by combining multicomponent processes and post-functionalizing the adducts...