4.5 4.0 3.5 3.0 2.5 2.0 1.5 ppm
1
H
4.5 ppm 3.3 ppm 1.2 ppm
5.33 Hz
(d)
5.33 Hz
(q)
1H 6H 3H
C
4
H
10
O
2
H
3
C CH
H
3
C
CH
If the carbon atoms of the two fragments are joined
together, the coupling patterns of both multiplets can be
well explained.
In the case of CH, of course, two free valences are missing.
5.33 Hz
A coupling constant of 5.33 Hz is somewhat small for
vicinal coupling. 7 Hz would be ideal. On the other hand, a
wide-range coupling across four single bonds would be
much smaller, about 0.5 Hz.
Let us now replace CH
with OH on a trial basis.