Addition and Cyclization Reactions in the Thermal Conversion of Hydrocarbons with an Enyne Structure, 4. Formation and Rearrangements of Bicyclic C10H8 Aromatics from 1‐Phenyl‐1‐buten‐3‐yne

Abstract

AbstractThe thermal conversion of 1‐phenyl‐1‐buten‐3‐yne (1) into the cycloisomerization products naphthalene (2), azulene (3), and 1‐methylene‐1H‐indene (4) has been studied at temperatures between 550 and 1000°C, a reaction time of approximately 0.3 s at 13 Torr (FVP) and at low partial pressures in a quartz flow system. The results obtained by FVP as well as in the presence of chemically modified diluent gases suggest a predominance of unimolecular cycloisomerizations to 2 and 3 which are, however, always accompanied by radical cyclization reactions to 2 and 4 even under FVP conditions if temperatures above 550°C are applied.