No-D NMR study of the pathway for n-BuLi "oxidation" of 1,5-cyclooctadiene to dilithium cyclooctatetraene dianion [Li2COT2-].
[Reaction: see text] 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.
Hoye
Thomas R
TR
Department of Chemistry, 207 Pleasant St., SE, University of Minnesota, Minneapolis, Minnesota 55455, USA. hoye@chem.umn.edu
Kabrhel
James E
JE
Hoye
Rebecca C
RC
D000466:Alkadienes / Q000737:chemistry*; D000838:Anions; D006844:Hydrocarbons, Cyclic / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction
D000466:Alkadienes; D000838:Anions; D006844:Hydrocarbons, Cyclic; D009942:Organometallic Compounds; C434823:n-butyllithium; C439868:1,5-cyclooctadiene; D008094:Lithium