284
J. C. Pardo-Novoa and C. M. Cerda-García-Rojas
O
O
O
HO
O
O
O
O
O
O
HO
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
OH
O
O
O
O
9
6
1
8
6
1
1
7
1
0
7
1
3
7
1
2
7
1
The methodology for the configurational analysis of sesquiterpenes 174–213
followed a similar strategy to the examples describes above. The sequence involved
measurement of the ECD spectrum in a selected solvent, followed by calculation
of the ECD curves for the most probable enantiomer, usually employing a timedependent DFT method at a confidence level of theory, and comparison between the
curves. It is important to mention that if an analyzed structure has several conformers,
the calculated spectra of each conformer will require Boltzmann-averaging to obtain
the ECD calculated curve. If this spectrum is comparable with its experimental
counterpart, the absolute configuration of the studied compound can be assigned
according to the configuration of the calculated molecular model. Table 2 summarizes
illustrative works that were carried out using this methodology.