Premium
X‐Ray Structure Analyses of syn / anti ‐Conformers of N ‐Furfuroyl‐, N ‐Benzoyl‐, and N ‐Picolinoyl‐Substituted (2 R )‐Bornane‐10,2‐sultam Derivatives
Author(s) -
Koszewska Karolina,
Piątek Anna,
Chapuis Christian,
Jurczak Janusz
Publication year - 2008
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.200890153
Subject(s) - chemistry , heteroatom , conformational isomerism , lone pair , crystallography , stereochemistry , crystal structure , dipole , ring (chemistry) , molecule , organic chemistry
The synthesis and the X‐ray structure of the three new N ‐(arylcarbonyl)‐substituted derivatives 2a – 2c of (2 R )‐bornane‐10,2‐sultam are presented and discussed. Direct comparison of the solid‐state analyses shows that the dipole‐directed SO 2 /CO anti‐ / syn‐ conformations may be very sensitive to weak electronic/electrostatic repulsions of the heteroatom lone pairs. The optimum interactions are reached when the lone pair of the β ‐positioned heteroatom is oriented in the O(3)C(11)N(1) plane. Such rare syn ‐conformations may be observed with at least up to 1.8 kcal/mol higher energy as compared to their ground states. Additionally, these anti / syn‐ conformations are also very sensitive to external influences such as, for example, the crystal‐packing forces.