Long-range functional group translocations in acyl migrations are not rare – The Friedel-Crafts acyl rearrangement cases

Functional Group Translocations (FGTs) are “transformations that preserve the molecular formula, the identity of the functional group, and the carbon framework, while altering only its position” ( Chem . Soc . Rev ., 2026, 55:7365–7404). Short-range (1,2) migration translocations and long-range (1, n ) ( n > 2) migration translocations were considered. The Brief Report demonstrates that long-range acyl-migration translocations (aka acyl group translocations) are not rare. Cases of acyl-migration translocations in Friedel-Crafts acyl rearrangements of polycyclic aromatic ketones and derivatives thereof are described, both reversible and irreversible processes. The polycyclic aromatic hydrocarbon systems under study were naphthalene (NA), fluorene (FL), anthracene (AN), phenanthrene (PHN), pyrene (PY) and fluoranthene (FT). The heterocyclic indole (IN) ring system and benzene are also included. The potential 1,2-intramolecular translocations of the migrating substituents are noted. The regioselectivity of FGT acyl migrations in Friedel-Crafts acyl rearrangements depends on the electronic and steric properties of the aromatic ring systems of the substrates, the sigma-complexes and the transition states thereof and on kinetic control versus thermodynamic control. Thus, long-range acyl migrations should not be considered exceptional cases of translocations. The Brief Report highlights the relatively frequent cases of Friedel-Crafts acyl-migration translocations, which may contribute to the recognition of the importance of FGTs in drug discovery and materials chemistry. The Brief Report is consistent with the narrow definition of FGT, as compared with rearrangement.