What can Grignard react with?

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Answer 1 · 2016-07-07T09:04:23

Typically we react Grignard reagents with carbonyl species.

The best way to make a carboxylic acid is to pour the Grignard reagent onto dry ice:

#R-MgX + CO_2(s) rarr R-C(=O)O^(-)""^(+)MgX#

Grignards will react with aldehydes and ketones to give secondary and tertiary alcohols:

#R-MgX + R'C(=O)H rarr R'RC(-O^(-))""^(+)MgX#

Grignards will react with epoxides to extend the carbon by 2 carbons:

#R-MgX + C_2H_4O rarr R-CH_2CH_2O^(-)""^(+)MgX#

The reaction with alkyl halides is generally unsuccessful. But Grignards will also react with any protic reagent, i.e. alcohols or water:

#RCH_2-MgX + D_2O rarr RCH_2D + MgXOD# #(D=""^2H)#

The water sensitivity of Grignard reagents is the reason why we take considerable precaution to perform these reactions under anhydrous conditions.