Question

Why does a Grignard reaction not react to water?

Answer 1

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Explanation:

`R-MgX + H_2O rarr R-H + Mg(OH)X`

A Grignard will react rapidly and irreversibly with water as shown to give the magnesium salt and parent alkane. Sometimes this reaction is used to label alkanes with deuterium (`""^2H`) or tritium (`""^3H`) labels:

`RCH_2MgX + D_2O rarr RCH_2D + Mg(OH)X`

`D=""^2H`