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Conformational Analysis and CD Calculations of Methyl‐Substituted 13‐Tridecano‐13‐lactones
Author(s) -
Voloshina Elena,
Fleischhauer Jörg,
Kraft Philip
Publication year - 2005
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200590001
Subject(s) - conformational isomerism , chemistry , basis set , computational chemistry , lactone , density functional theory , stereochemistry , molecule , organic chemistry
Conformational models covering an energy range of 3 kcal/mol were calculated for (13 S )‐tetradecano‐13‐lactone ( 3 ), (12 S )‐12‐methyltridecano‐13‐lactone ( 4 ), and (12 S ,13 R )‐12‐methyltetradecano‐13‐lactone ( 8 ), starting from a semiempirical Monte‐Carlo search with AM1 parametrization, and subsequent optimization of the 100 best conformers at the 6‐31G*/B3LYP and then the TZVP/B3LYP level of density‐functional theory. CD Spectra for these models were calculated by the time‐dependent DFT method with the same functional and basis sets as for the ground‐state calculations and Boltzmann weighting of the individual conformers. The good correlation of the calculated and experimental spectra substantiates the interpretation of these conformational models for the structure–odor correlation of musks. Furthermore, the application of the quadrant rule in the estimation of the Cotton effect for macrolide conformers is critically discussed.