Estimation of sp3 Chemical Shifts

A General Approach for Calculating Proton Chemical Shifts for Methyl, Methylene, and Methine Protons When There Are One or More Substituents within Three Carbons

Philip S. Beauchamp and Rodolfo Marquez
J. Chem. Ed., 1997, 74(12), 1483-1485.

Base Values: CH3- Methyl=0.9 ; -CH2- Methylene=1.2 ; -CH- Methine=1.5

Substituent Constants:
Xalphabetagammagroup
R-0.00.00.0alkyl
R2C=CR-0.80.20.1alkene
RC(C-0.90.30.1alkyne
Ar-1.40.40.1aromatic
F-3.20.50.2fluoro
Cl-2.20.50.2chloro
Br-2.10.70.2bromo
I-2.00.90.1iodo
HO-2.30.30.1hydroxyl
RO-2.10.30.1ether
R2C=CRO-2.50.40.2vinyl ether
ArO-2.80.50.3aryl ether
OHC-1.10.40.1aldehyde
RCO-1.20.30.0ketone
ArCO-1.70.30.1aryl ketone
RCO2-2.80.50.1ester
ArCO2-3.10.50.2aromatic ester
HO2C-1.10.30.1carboxylate
RO2C-1.10.30.1carboxyl ester
ClOC-1.80.40.1acid chloride
H2N-1.50.20.1amine
RCONH-2.10.30.1amide-N-
H2NOC-1.00.30.1amide-C-
N(C-1.10.40.2nitrile
O2N-3.20.80.1nitro
HS-1.30.40.1sulfhydryl
RS-1.30.40.1sulfide
ArSO3-2.80.40.0sulfonate
RSO-1.60.50.3sulfoxide
RSO2-1.80.50.3sulfone
alpha= directly attached substituent
beta = once-removed substituent
gamma = twice-removed substitutent

Back to 1H Shift Prediction

Examples

The following example is taken from Beauchamp and Marques.

abc
Actual (ppm)4.03.51.2
Base1.21.20.9
C=C-0.80.20.1
R-O-2.12.10.3
Total 4.13.51.3

The a protons would have table entries:
Alpha Substituents:
The beta and gamma substituents need not be changed.
The b protons would have table entries:
Alpha Substituents:
Beta Substituents:
The gamma substituents need not be changed.
Use the c protons as test case.
Back to 1H Shift Prediction