In order to develop the logic of organic synthesis, a thorough knowledge of the individual chemical reactions which make up a method of synthesis is required. New types of organic reactions are constantly being invented all over the world and give rise to new methods. Many of these have been created and developed by E.J. Corey.
    In many cases E.J. Corey uses a metal, often a transition metal, to keep the reactive centres of two molecules together and to affect the reactivity of certain carbon atoms in each unit.
    In the picture, a reaction is shown by which a new carbon-carbon bond is created using copper and lithium. This type of reaction is very common and a large number of different organic groups can be bound to one of the carbons in a double bond next to a carbonyl group .
     However, it is not sufficient to know the starting material and the product in a reaction. To predict the three-dimensional structure of the product, its stereochemistry, one has to understand the reaction mechanism in great detail. E.J. Corey has revealed the detailed mechanisms of many useful reactions.