Reactions of Alkyl Halides: Grignard Reagents
Start with the big picture
Grignard reagents have the general formula RMgX and are prepared from an organic halide and magnesium in anhydrous ether or THF under an inert atmosphere. Their carbon behaves like a carbanion, making them strong bases and nucleophiles—but also highly sensitive to water, alcohols, oxygen, and acidic groups. Reactions with formaldehyde, aldehydes, and ketones produce alcohols after acidic work-up; reaction with CO₂ forms carboxylic acids, while epoxide opening extends a carbon chain. The broader lesson also considers reactions with esters, acid chlorides, and nitriles, along with practical limitations such as incompatible functional groups, side reactions, and selectivity effects.
What you'll learn
- Describe how Grignard reagents are prepared and why dry, inert conditions are required.
- Explain the carbanion-like behavior of RMgX as a base and nucleophile.
- Predict alcohol products from Grignard additions to formaldehyde, aldehydes, and ketones.
- Recognize Grignard reactions that form carboxylic acids, ketones, or extended carbon chains.
- Identify key limitations, side reactions, and functional groups that may require protection.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
