N
X
C
Hal
O
N
S
P Si
Natural
Products
Solvents
C
C
C
C C
C
4.11 Carbonyl Compounds
135
4.11 Carbonyl Compounds
4.11.1 Aldehydes
Additivity Rule for Estimating the 13 C Chemical Shifts of Aldehyde
Carbon Atoms (δ in ppm)
δ C=O = 193.0 + ∑ Z i
–C β –C α –CHO
Substituent i
Z α
Z β
–C
6.5
2.6
–CH=CH 2
-0.8
0.0
–CH=CH–CH 3
0.2
0.0
–phenyl
-1.2
0.0
13 C Chemical Shifts and 13 C- 1 H Coupling Constants with the Formyl
Protons of Aldehydes (δ in ppm, J in Hz)
CHO
CHO
O
H 2 C
CHO
H 3 C
CHO
CHO
CHO
CHO
CHO
Cl 3 C
CHO
CHO
CHO
31.3
15.5
23.4
13.8
22.4
83.1
24.3
43.6
81.8
26.1
25.2
25.2
50.1
41.1
42.4
15.7
5.2
36.7
13.3 45.7
197.0
202.7
200.5
204.6
194.4
176.8
204.7
192.0
136.7
129.7
129.0
134.3
138.6
137.8
205.6
201.3
201.6
176.9
95.3
1 J CH 172.0
1 J CH 168.1
1 J CH 169.0
1 J CH 172.0
2 J CH 26.7
1 J CH 175.0
2 J CH 24.2
1 J CH 170.8
2 J CH 25.2
1 J CH 208.5
2 J CH 46.3
1 J CH 173.2
2 J CH 26.9
1 J CH 197.9
2 J CH 33.2
2 J CH 23.6
2 J CH 24.8