20430-62-0Relevant articles and documents
CHAIR-BOAT INTERCONVERSION IN CYCLIC SEVEN-MEMBERED AMIDES AND RELATED STRUCTURES.
Majchrzak, Michal W.,Kotelko, Antoni,Guryn, Roman,Lambert, Joseph B.,Wharry, Stephen M.
, p. 1075 - 1080 (1981)
The transition state to ring reversal has been examined in a series of 7-membered rings related to caprolactam.The structural changes associated with introduction of Me groups, with alteration of the nature of the C=N double bond, with ring fusion, or with introduction of a second, nonconjugated N atom perturb the transition state to ring reversal.From 1H and 13C NMR studies, we find that the lactam bond itself favors a different transition state from that present in cycloheptene.With some exceptions, the observed barriers are consistent with TS II, in which ring reversal begins with movement of the C5 end of the ring, or with TS III, in which ring reversal begins with C3-C4 bond torsion.The conclusions are consistent with the structural changes that result from the functional and steric alterations.
