ABSTRACT
Alkenes are, due to the extra electron density around the π bond, electron-rich. This renders alkenes basic and nucleophilic. In this chapter, readers are introduced to alkene addition reactions, where a reagent is added to the alkene π bond to produce a saturated product. The reactions proceed through cationic (carbocation or onium ion) intermediates, which dictate the regiochemical outcome of the addition. In general, alkene additions tend to add the more electronegative component to the more substituted carbon atom and the less electronegative (typically H atom) to the less substituted carbon atom. This Markovnikov regiochemistry will be understood in terms of differences in energy between different reactive intermediates. Reactivity patterns introduced in this chapter will inform reactivity patterns seen in subsequent chapters.
