1,5‐Cyclooctadiyne. Preparation and Reactivity

Abstract

Abstract 1,5‐Cyclooctadiyne 1 was isolated in 2 percent yield from polymerized butatriene 5 . Other oligomers of 5 were detected in the reaction mixture by combined GLC./MS. analysis but have not been identified. Diels ‐ Alder adducts of 1 with two equivalents of 1,3‐butadiene and of 2,3‐dimethyl‐1,3‐butadiene have been prepared. In the presence of strong base 1 isomerized to cyclooctatetraene. 5 was reformed by photolysis of 1 . Attempts to prepare transition metal complexes of 1 failed. Effects of ring strain and of transannular interaction on the reactivity of 1 are discussed. The dimerization of 5 to 1 is predicted to be strongly exothermic.