SN2 reaction of water with alkyl halides to give alcohols
Description: Primary or methyl halides (or tosylates) will react with water to give alcohols. This is an SN2 reaction.
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Notes: X here is a halide (Cl, Br, I) or sulfonate (OTs, OMs)
Examples:
Notes: Water is a poor nucleophile and generally isn’t strong enough to displace a leaving group from a secondary alkyl halide.
Mechanism: In this reaction water attacks the carbon in an SN2 reaction displacing the leaving group (bromide in this case) (Step 1, arrows A and B). The bromide ion then removes a proton from the oxygen, providing the neutral alcohol and HBr.
Notes: It’s also reasonable to use water as the base here in the second step instead of Br(-). In fact it’s probably more reasonable to do so since water is a stronger base than Br(-).
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{ 2 comments… read them below or add one }
Why does it say NaOH instead of H20?
NaOH is a much better nucleophile than water; for practical purposes it’s much faster to use than H2O.