Beta-eliminations giving multiple bonds between carbon and other ELEMENTS

Beta-eliminations giving multiple bonds between carbon and other elements 

Elimination reactions which give rise to multiple bonds between carbon and a heteroatom occur with particular facility and show many of the characteristics of olefin-forming processes. Most often one of the eliminating fragments is a hydrogen atom, which is easily removed from a heteroatom and the choice of mechanism, between an anion or a concerted process, will depend on the lability of the beta carbon-X bond, e.g. 

These types of reaction are more realistically considered as the reversal of the well-known addition reactions to multiple bonds and thus are not discussed in this chapter. 

When hydrogen is removed from a carbon atom (216), 

There are numerous examples of reactions leading to multiple bonds between a carbon atom and a heteroatom but in the space available in this review it is only possible to mention a few of the interesting kinetic techniques which have led to an understanding of some of the reaction mechanisms involved. 

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