The Wittig reaction is a chemical reaction used to form alkenes from aldehydes or ketones. It involves the reaction of a phosphonium ylide with a carbonyl compound, resulting in the formation of an alkene and a byproduct of a phosphine oxide. This reaction is valuable in organic synthesis for creating double bonds in a straightforward manner. The Wittig reaction is named after the German chemist Georg Wittig, who developed the method in the 1950s. It has become a fundamental tool in organic chemistry, particularly in the synthesis of complex molecules, including natural products and pharmaceuticals.