Fragmentation of Ketone (x-cleavage + McLafferty Rearrangement)
1)
X-Cleavage
"
.
¤ eq
유
The Ketone will be hit with beam of electrons and the most electron to be knocked out
a
, likely will be
of the
one
high-energy ,
non-bonding electrons off of
oxygen .
[
itt0.
しか
¤
「
.
유용 , E ⑧
%
(t)
Cia
←
resonance stabilized
The radical electron will form half of a triple bond the other half of the triple bond will be formed by
,
the bond between the Carbony carbon and Alpha (a) Carbon. This will form radical
breaking the a
Onto the alpha carbon .
This will form triple bond to the and three carbon radical
a on
oxygen , a .
2) McLafferty Rearrangement
Only possible if there is at least 3 carbons on either side of the Ketone .
o 11 [ ⑥+) H
"]
:
.
:O : .
e- ,
간 니
K
· It
+
B 3
B
.
α α
resonance stabilized
cation
The radical form bond between
on the
Oxygen will half the it and
Hydrogen , the other half of
this bond will some from the U-H bond .
The other electron of this bond will be used to
form a pibond between U and B
. The other half of this pibond comes from the bond
between B other half of the X-B bond radical
breaking X and .
The forms a on x-carbon .
The result is unusual . Usually we get a cation and a radical ,
but this result is both the cation
and the radical .
This is the result of the McLafferty Rearrangement.
1)
X-Cleavage
"
.
¤ eq
유
The Ketone will be hit with beam of electrons and the most electron to be knocked out
a
, likely will be
of the
one
high-energy ,
non-bonding electrons off of
oxygen .
[
itt0.
しか
¤
「
.
유용 , E ⑧
%
(t)
Cia
←
resonance stabilized
The radical electron will form half of a triple bond the other half of the triple bond will be formed by
,
the bond between the Carbony carbon and Alpha (a) Carbon. This will form radical
breaking the a
Onto the alpha carbon .
This will form triple bond to the and three carbon radical
a on
oxygen , a .
2) McLafferty Rearrangement
Only possible if there is at least 3 carbons on either side of the Ketone .
o 11 [ ⑥+) H
"]
:
.
:O : .
e- ,
간 니
K
· It
+
B 3
B
.
α α
resonance stabilized
cation
The radical form bond between
on the
Oxygen will half the it and
Hydrogen , the other half of
this bond will some from the U-H bond .
The other electron of this bond will be used to
form a pibond between U and B
. The other half of this pibond comes from the bond
between B other half of the X-B bond radical
breaking X and .
The forms a on x-carbon .
The result is unusual . Usually we get a cation and a radical ,
but this result is both the cation
and the radical .
This is the result of the McLafferty Rearrangement.
