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Conformation of α , α , α′ ‐Trisubstituted Cyclododecanone
Author(s) -
Wang MingAn,
Zhang Ning,
Lu HuiZhe,
Wang DaoQuan
Publication year - 2007
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200790223
Subject(s) - chemistry , geminal , moiety , ring (chemistry) , alkane stereochemistry , crystallography , crystal structure , cyclohexane conformation , stereochemistry , computational chemistry , molecule , organic chemistry , hydrogen bond
Ten α , α , α ′‐trisubstituted cyclododecanones were synthesized and characterized by elemental analyses, infrared, 1 H NMR and 13 C NMR spectra, and X‐ray diffraction. NMR data could not give conformational information clearly, but some of their ring skeleton conformations of cyclododecanone moiety were showed to remain the unchanged [3333]‐2‐one conformation with little distortion, while the others were changed to the [3324]‐2‐one conformation in their crystal structures. These are consistent with the results of molecular mechanics calculation with Sybyl 6.9 software and Tripos force field, and semi‐empirical quantum calculation with AM1 method in Gaussian 98 software. Two geminal substituting groups are located at α ‐corner carbon atom, and the third group is at α ‐side‐ exo carbon atom in both conformations. Both [3333]‐2‐one and [3324]‐2‐one conformations are present in a dynamic equilibrium in the solution, but only one preferred conformation exists in the crystal solid.