Grignard reaction
The Grignard reaction (pronounced ) is an organometallic chemical reaction in which alkyl- or aryl-magnesium halides (Grignard reagents) attack electrophilic carbon atoms that are present within polar bonds (for example, in a carbonyl group as in the example shown below). Grignard reagents act as nucleophiles. The Grignard reaction produces a carbon–carbon bond. It alters hybridization about the reaction center.  The Grignard reaction is an important tool in the formation of carbon–carbon bonds. It also can form carbon–phosphorus, carbon–tin, carbon–silicon, carbon–boron and other carbon–heteroatom bonds.