OCRa A level Module 6 Carbonyl Compounds Notes

12 ·

09 .


23

Module 6 .


Carbonyls

Describe how the i-bond forms in a care
mys group
:




-
c =
0

/ -
-



sideways overlapping of adjacent
R2 -
C -
O p-orbital
&



it above and below the C-0
.
-
& the =0 bond does not react readily with electrophiles :

-


the (is f* +
the C 2 =
becomes palaried
-the it bind elections are unavailable due to
being polarized
-



electrophiles are repelled
+
-




nuclephiles are attracted to the Cf



Reduction of Carbonyls to form alcinols.



aldehydes
+
ketones can be reduced to
-



an alcohol




[]
-Reducing Agent :
NaBH4(an)
represented as [H]
in equasions.

, example 1 :
Reduction of Propanal

H H H

5
H
I


j c
I I
+
2[H] > c OH

-
-

H
-




H
- - -
-
-




11
It H It H


Propanal Propan-1-01




example 2 : Ketone


H H



-
It It It
It 0 It
1 I
I 1
- - -
+ +
2) - -
- - -
- -
-




I & I I & I
I I

H H H (t H H H H It


Pentone Pentan-1-01



Mechanism :
Nucleophilic Addition

BHG acts a source of : H-
-




as



Example :
Ethanal (Aldenyde) st
jo+St
H
,



f- H
I 8 H
It




H-c- I
I
I
> H - -
H-c-C-O
-
-




H
iH
·
intermediate I
products :



ethanol +
hydroxide ion-