Reaction of a Grignard reagent questions?
1) How would these compounds be arranged in order of increasing reactivity towards attack of the Grignard reagent at the carbonyl carbon atom: methyl benzoate, benzoic acid, benzaldehyde, acetophenone, benzoyl chloride. Explaining the basis for each.
2) What is/are the product(s) of reaction of each of the above carbonyl containing compounds with an excess of a Grignard reagent, RMgBr?
3) How might primary, secondary, and tertiary alcohols be prepared from a Grignard reagent, RMgBr, and a suitable carbonyl-containing compound? What would be the chemical equations, with stoichiometry, for these preparations?
- ErebosLv 61 decade agoFavorite Answer
benzoyl chloride's pretty good. no acidic hydrogens whatsoever
methyl benzoate. a good ester, but some weakly acidic hydrogens
benzaldehyde. hydrogen on the aldehyde is a poor acid,
acetophenone, alpha hydrogen can be deprotonated instead
benzoic acid. no question, the grignard will simply take the acid hydrogen and not attack the carbon at all
respectively, in the above order
lose the Cl, add the R
lose the methoxide, add R to make ketone, then another R will attack the carbonyl, adding on, and making the ketone a tertiary alcohol
add R, make aldehyde a secondary alcohol
again, secondary alcochol, with an extra R
you'd get benzoate(-) and MgBr(+), along with a full alkane R. ruined grignard
primary, react with formladehyde
secondary, react with aldehyde
tertiary, react with ketone/ester derivative
- 4 years ago
Break either the bond between C2 and C3 or C3 and C4. C2-C3 gives you ethylmagnesium bromide and 2-methylpentenal. C3-C4 gives you 2-pentylmagnesium bromide and pentanal.