Myers–Saito and Schmittel cyclization of hepta-1,2,4-triene-6-yne: A theoretical REKS study

Abstract

Spin-restricted ensemble-referenced Kohn–Sham (REKS) calculations have been performed on the cyclization process of hepta-1,2,4-triene-6-yne leading to a five-membered ring (Schmittel cyclization) or a six-membered ring (Myers–Saito process), both products being biradicals. Geometries compare well with density functional as well as ab initio calculations and experimental measurements from the literature. Relative energies and singlet–triplet gaps were studied and compared with BCCSD(T) calculations.