<i>para</i>‐ and <i>ortho</i>‐Quinodimethane Intermediates with Cumulative Double Bonds

Abstract

The highly reactive intermediates 1 and 2 with cumulative double bonds in para and ortho positions, respectively, react to give products with isolated triple bonds. Intermolecular dimerization of 1 yields a paracyclophanetetrayne, which assumes two conformations in the crystal. Compound 2 reacts by intramolecular cyclization affording a highly strained cycloocta-3-ene-1,5-diyne derivative.