Organolithium reagents are a class of chemical compounds that contain a carbon-lithium bond. They are highly reactive and are commonly used in organic synthesis to form new carbon-carbon bonds. These reagents can be prepared by reacting alkyl or aryl halides with lithium metal in an organic solvent, making them valuable tools in the field of organic chemistry. Due to their strong nucleophilic properties, organolithium reagents can react with a variety of electrophiles, including carbonyl compounds and alkenes. They are essential in the synthesis of complex organic molecules, including pharmaceuticals and natural products, and are known for their ability to generate a wide range of functional groups.