Observed and calculated <sup>1</sup>
H and <sup>13</sup>
C chemical shifts induced by the <i>in situ</i>
oxidation of model sulfides to sulfoxides and sulfones
quantum chemical calculations have been tested to reproduce the observed (1)H and (13)C chemicalshifts of the starting sulfides and their oxidation products. It has been shown that the determination of the energy-minimized conformation is a very important condition for obtaining realistic data in the subsequent calculation of the NMR chemicalshifts. The correlation between calculated and observed chemical