RMgCl

RMgCl, also known as a Grignard reagent, is an organomagnesium halide compound with the general formula RMgX, where R is an organic group and X is a halogen. These compounds are widely used in organic synthesis as nucleophilic sources of R groups. They are prepared by the reaction of an organohalide with magnesium metal in an ethereal solvent, such as diethyl ether or tetrahydrofuran. The reaction is typically initiated by activating the magnesium surface.

Grignard reagents are highly reactive and are sensitive to moisture and air, requiring anhydrous conditions for their preparation and use. They react readily with electrophilic species, making them valuable for forming new carbon-carbon bonds. Common reactions include addition to carbonyl compounds (aldehydes, ketones, esters, and acid chlorides) to form alcohols, and reaction with epoxides to form alcohols. They can also react with carbon dioxide to form carboxylic acids, and with alkyl halides to form alkanes, though this last reaction is less common due to potential side reactions. The magnesium atom in the Grignard reagent is polarized, with a partial positive charge, while the organic group attached to it carries a partial negative charge, enabling its nucleophilic character.