Unexpected reactivity difference between iodo-alkene moieties of steroids possessing remote lactame or cycloalkane structural units: a theoretical approach.
The steroidal ring A possessing cyclohexane vs. delta-valerolactame structures shows a 'long-range effect' on the reactivity of the 'iodovinyl' functionality of the ring D. The strikingly different reactivity of 17-iodo-16-ene functionality of steroids is explained on the basis of the redistribution of kinetic energy of the system. The vibrational energy localized on the 'iodovinyl' moiety proved to be determinant in the CI bond-breaking process. The appearance of the lactame moiety in the ring A supports a redistribution of the kinetic energy on the molecule. As a result, a drastic decrease in C-I bond stretching has been obtained, which could diminish the C-I bond breaking, and therefore, results in decreased reactivity of the iodovinyl moiety in agreement with experimental findings.
Kunsági-Máté
Sándor
S
Faculty of Sciences, Department of General and Physical Chemistry, University of Pécs, H-7624 Pécs, Ifjúság 6, Hungary. kunsagi@ttk.pte.hu
Skoda-Földes
Rita
R
Szepes
László
L
Végh
Eszter
E
Kollár
László
L
D000475:Alkenes / Q000737:chemistry*; D003198:Computer Simulation; D003516:Cycloparaffins / Q000737:chemistry*; D017613:Iodine Compounds / Q000737:chemistry*; D007700:Kinetics; D007769:Lactams / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D013256:Steroids / Q000737:chemistry*; D013329:Structure-Activity Relationship
D000475:Alkenes; D003516:Cycloparaffins; D017613:Iodine Compounds; D007769:Lactams; D013256:Steroids