Increment system for estimation of chemical shifts of alkene carbons
Formula:
| Substituent | I1 | I2 | Comment |
| -H | 0 | 0 | |
| -CH3 | 10.6 | -8.0 | |
| -C2H5 | 15.5 | -9.7 | |
| -CH2CH2CH3 | 14.0 | -8.2 | n-propyl |
| -CH(CH3)2 | 20.3 | -11.5 | i-propyl |
| -CH2CH2CH2CH3 | 14.7 | -9.0 | n-butyl |
| -C(CH3)3 | 25.3 | -13.3 | t-butyl |
| -CH=CH2 | 13.6 | -7.0 | |
| -CC-R | -7.5 | 8.9 | alkyne |
| -C6H5 | 12.5 | -11.0 | |
| -CH2Cl | 10.2 | -6.0 | |
| -CH2Br | 10.9 | -4.5 | |
| -CH2OR | 13.0 | -8.6 | |
| -CHO | 13.1 | 12.7 | |
| -COCH3 | 15.0 | 5.9 | |
| -COOH | 4.2 | 8.9 | |
| -COOR | 6.0 | 7.0 | |
| -CN | -15.1 | 14.2 | nitrile |
| -OR | 28.8 | -39.5 | |
| -OOCR | 18.0 | -27.0 | |
| -NR2 | 16.0 | -29.0 | |
| -N(CH3)3+ | 19.8 | -10.6 | |
| -NO2 | 22.3 | -0.9 | |
| --SR | 19.0 | -16.0 | |
| -F | 24.9 | -34.3 | |
| -Cl | 2.6 | -6.1 | |
| -Br | -7.9 | -1.4 | |
| -I | -38.1 | 7.0 | |
Example: Methyl methacrylate
