N
X
C
O
N
S
Hal
Solvents
Natural
Products
P Si
C
C
C C
C
C
90
4 13 C NMR
4.2.2 Coupling Constants
13 C- 1 H Coupling Constants (|J CH | in Hz)
Coupling through one bond
Coupling through two bonds
Additivity rule for the estimation of 2 J CH of alkenes: see [2].
Coupling through three bonds
The trans- 1 H–C=C– 13 C coupling constant of alkenes is always larger than the corresponding cis coupling constant so that an assignment is possible if both isomers
are available: see [3].
13 C- 13 C Coupling Constants (|J CC | in Hz)
4.2.3 References
[1] R.H.A.M. Janssen, R.J.J.Ch. Lousberg, M.J.A. de Bie, An additivity relation
for carbon-13 chemical shifts in substituted allenes, Recl. Trav. Chim. Pays-Bas
1981, 100, 85.
[2] U. Vögeli, D. Herz, W. von Philipsborn, Geminal C,H spin coupling in substituted alkenes, Org. Magn. Reson. 1980, 13, 200.
[3] U. Vögeli, W. von Philipsborn, Vicinal C,H spin coupling in substituted alkenes.
Org. Magn. Reson. 1975, 7, 617.
C C
H
H 3 C
13
COOH
13
CH 3
3 J ac 4.1
3 J bc 8.1
3 J ac 7.6
3 J bc 14.1
3 J ab 6.9
3 J ac 13.2
3 J ab 7.7
3 J ac 7.4
3 J ac 7.6
3 J bc 14.1
C C
H
H
13
CH 3
H
CH 2 CH 2
CH 2 C CH 2
1 J CH 156.4
2 J CH -2.4
1 J CC 67.6
1 J ab 70.0
1 J bc 41.9
3 J ac 7.6
3 J bc 12.6
1 J CC 98.7
1 J ab 68.8
1 J bc 53.7
2 J ac <1
3 J ad 9.0
2 J CH 6.9
1 J CH 167.8
13
C
H
H
H
H
13
C
H
H
Cl
H
C C
H
H
13
CH 3
Cl
C C
H
H
13
COOH
H
C C
H
H
13
COOH
CH 3
CH 2 CH 2
CH 2 C CH 2
CH 2 CH CH 3
a
a
b
b
c
c
d
a
a
a
a
a
a
b
b
b
b
b
b
c
c
c
c
c
c
C C
H 3 C
H
13
COOH
13
CH 3