CHEMISTRY OF 1,2-5,6-DIBENZOCYCLOOCTATETRAENE DIANION

The reactions of sym-dibenzocyclooctatetraene dianion (2) with carbon dioxide, acetyl chloride, acetone, benzoyl chloride, acetaldehyde, diphenyldichloromethane, and benzyl chloride have been investigated. Carboxylation gave the predictable mixture of trans and cis,β-dicarboxylic acids, the latter in the form of its anhydride. Condensation with 1 mol of acetyl chloride led to the 1:1 product, ketone 10, resulting from rapid intramolecular proton transfer in the intermediate monoanion, rather than intramolecular alkylation as in the parent nonannulated COT dianion. Reaction with acetone gave a 1:1 product, whereas the title dianion behaved as an electron source toward benzoyl chloride and the remaining substrates listed above. The structure of cts-bis [(benzoyl)oxy]stilbene, one of the two reduction products from 2 and benzoyl chloride, was established by single-crystal X-ray analysis. The X-ray results were used as a test of a new method of treating “unobserved” reflections. © 1979, American Chemical Society. All rights reserved.