Why must a Grignard reagent be made and used in perfectly dry conditions?
A Grignard reagent (R–MgX) has a strongly nucleophilic, basic carbon.
A Grignard reagent (R–MgX) has a strongly nucleophilic, basic carbon. Water has an acidic O–H proton, so even a trace of moisture instantly protonates the reagent, converting it to an unreactive alkane (R–H) and destroying it before it can do its job of building a C–C bond with a carbonyl. That's why the glassware, solvent and even the air must be moisture-free.
Key point
Grignards are destroyed by any water (protonated to R–H), so everything must be anhydrous.
Common mistake
assuming a little moisture won't matter.
Memory tip
water kills a Grignard on contact — keep it bone-dry.
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