Chapter 14, Problem 24P

(a) In 1960 T. Katz (Columbia University) showed that cyclooctatetraene adds two electrons when treated with potassium metal and forms a stable, planar dianion, $C_8{H}_8^{2-}$ (as the dipotassium salt):

Use the molecular orbital diagram given in Fig. 14.7 and explain this result.

(b) In 1964 Katz also showed that removing two protons from the compound below (using butyllithium as the base) leads to the forma-tion of a stable dianion with the formula $C_8{H}_6{}^{2-}$ (as the dilithium salt).

Propose a reasonable structure for the product and explain why it is stable.