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Carbonyl Reactions

Three isomeric carbonyl starting materials are available for your use. They are shown on the left below. Using one of these compounds, and selecting reagents from the list on the right, indicate how the products a) through o) might be prepared. Each question requires two responses. Under Carbonyl Cpd. enter 1, 2 or 3. Under Reagents enter a letter A through F, corresponding to your selection.

Carbonyl Cpd. Reagents
1.   (CH3)2CHCOCH3
3-methyl-2-butanone

2.   (CH3)2CHCH2CHO
3-methylbutanal

3.   CH3CH2COCH2CH3
3-pentanone
A.
Jones' reagent
CrO3 in H3O(+)
B.
C6H5MgBr (in ether)
followed by H3O(+) workup
C.
C2H5OH (excess)
acid-catalyst, heat (–H2O)
D.
NaBH4
in CH3OH
E.
(CH2)5NH (piperidine)
acid-catalyst, heat (–H2O)
F.
N2H4
KOH & strong heat

Carbonyl Compound Reagent(s)   Product Answer Evaluation
reaction arrow a) C6H5CH(OH)CH2CH(CH3)2
    3-methyl-1-phenyl-1-butanol
 

reaction arrow b) (CH3)2CHCH(OH)CH3
    3-methyl-2-butanol
reaction arrow c)
Enamine of 3-pentanone with piperidine: C=C bearing methyl and ethyl groups bonded to the piperidine nitrogen
reaction arrow d) C6H5C(OH)(C2H5)2
    3-phenyl-3-pentanol
reaction arrow e) (CH3)2CHC(OC2H5)2CH3
    2,2-diethoxy-3-methylbutane
reaction arrow f) (CH3)2CHC(OH)(C6H5)CH3
    3-methyl-2-phenyl-2-butanol
reaction arrow g) (C2H5)2C(OC2H5)2
    3,3-diethoxypentane
reaction arrow h) (CH3)2CHCH2CH2OH
    3-methyl-1-butanol
reaction arrow i) (CH3)2CHCH2CH3
    2-methylbutane
reaction arrow j) (CH3)2CHCH2CO2H
    3-methylbutanoic acid
reaction arrow k)
Enamine of 3-methyl-2-butanone with piperidine: isopropyl-substituted vinyl (C=CH2) bonded to the piperidine nitrogen
reaction arrow l) CH3(CH2)3CH3
    pentane
reaction arrow m) (CH3)2CHCH2CH(OC2H5)2
    1,1-diethoxy-3-methylbutane
reaction arrow n) C2H5CH(OH)C2H5
    3-pentanol
reaction arrow o)
Mechanism of enamine formation from a ketone and secondary amine via protonated carbonyl, iminium ion, and proton shift to stereoisomeric enamines

Carbonyl Cpd. Reagents
1.   (CH3)2CHCOCH3
3-methyl-2-butanone

2.   (CH3)2CHCH2CHO
3-methylbutanal

3.   CH3CH2COCH2CH3
3-pentanone
A.
Jones' reagent
CrO3 in H3O(+)
B.
C6H5MgBr (in ether)
followed by H3O(+) workup
C.
C2H5OH (excess)
acid-catalyst, heat (–H2O)
D.
NaBH4
in CH3OH
E.
(CH2)5NH (piperidine)
acid-catalyst, heat (–H2O)
F.
N2H4
KOH & strong heat

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