Mechanism and Regioselectivity of an Unsymmetrical Hexadehydro-Diels–Alder (HDDA) Reaction

Hoye reported intramolecular hexadehydro-Diels–Alder (HDDA) reactions to generate arynes that functionalize natural product phenols and amines. In their studies, Hoye found that unsymmetrical tetraynes selectively form a single aryne. We report density functional theory (DFT) calculations that reveal the factors controlling the regioselectivity.