Question

provide methods for preparing following compunds by the Grignard method::

Provides methods for preparing the following compounds by the Grignard method:

Answer 1

Answer 2

1 & 2)

using grignards you could start out with 1-bromoethane, then add Mg in a polar solvent without H bonds, so diethyl ether is usually used. then you would have CH3CH2-+MgBr which is your grignard. now you would have to add propanal which is CH3CH2-CHO. the grignard attacks the carbonyl and after adding some acid you get the alcohol, and you have 3 pentanol.

to get 3-methyl-3-pentanol, do the same work up, except instead of adding propanal, add 2-butanone, then acid and you have your product. it is important to remember that you cannot have acidic protons in grignard reactions, so adding the acid should be the very last step, and it could just be H3O+.

treating propanal with ethyl magnsium bromide and then dilute acid will yield 3 pentanol

C2H5MgBr + O=CH-C2H5------- C2H5-CH(OH)-C2H5

treating 2 -butanone with ethylmagnesium bromide and then dilute acid will generate 3-methyl 3 pentanol

C2H5MgBr + CH3-CO-C2H5---- C2H5 -C(CH3)(OH)-C2H5

3)   

4)