No-D NMR pstudy of the pathway for n-BuLi "oxidation" of 1,5-cyclooctadiene to dilithium cyclooctatetraene dianion [Li ₂COT^2-]

(Chemical Equation Presented) The transformation of 1,5-cyclooctadiene (1) into cyclooctatetraene (3) by way of dianion 2 is an interesting reaction of considerable preparative value. The mechanism was initially suggested to involve lithium hydride loss from 4a/4b, followed by two deprotonations to produce 2. This No-D ¹H NMR study indicates the long-term stability of 4a/4b (in the absence of additional n-BuLi) and suggests a different mechanistic sequence, in which 4a/4b is deprotonated a second time prior to LiH ejection.