Assignment No 2
in which an aldehyde or ketone is converted into its
Enole is called enolization or keto-enol tautomerism.1
Chemistry of Carbonyl compound
Nature of carbonyl
compound and Reactivity;
compound is very versatile and it contains partial positive charge on carbon
and partial negative charge on oxygen.
points in its chemistry are;
and Oxygen are sp2 hybridized
form single bond with other R groups
lone pairs are present on oxygen atom
geometery or framework of carbonyl
compound is Trigonal Planner.
While the reactivity of carbonyl
compound is due to the presence of acidic ?-hydrogen.
in alkanes hydrogen is bonded to carbon by sp3 hybridization but the
electronegativity difference between carbon and hydrogen is so small due to which the attatched hydrogen
is less acidic.While in the case of aldehyde or ketone due to the presence of
carbonyl group to the ?-carbon the ?-hydrogen becomes more acidic.But still this ?-hydrogen is less
acidic then hydrogen of H2O.
two main factors responsible for acidity of carbonyl compounds are;
Inductive effect of carbonyl
compound increases the pocitive character
of conjugate base
above values shows that aldehyde and ketones are more acidic then sp3 hybridized Carbon as alkanes.Because
the removal of ?-hydrogen the conjugate
base formed is more stable in carbonyl containing compounds due to resonance
than sp3 hybridized carbon.
aldehyde and ketone are more acidic than ethers for the same reason which is
described above and ethers are less acidic because after removal of ?-hydrogen
in ethers the non-bonding electrons of OR and O compete for resonance.
is present between two carbonyl compounds then pka of ?-diketoester is more then pka of ?-diketones i.e ?-diketoester
is less acidic then ?-dietones.