Acid chlorides can be activated using a simple iodide source to undergo nucleophilic attack from a variety of relatively weak nucleophiles. These include Friedel-Crafts acylation of N-methylpyrroles, N-acylation of sulfonamides, and acylation reactions of hindered phenol derivatives. The reaction is believed to proceed through a transient acid iodide intermediate.
Wakeham, R. J., Taylor, J. E., Bull, S. D., Morris, J. A., & Williams, J. M. J. (2013). Iodide as an activating agent for acid chlorides in acylation reactions. Organic Letters, 15(3), 702-705. https://doi.org/10.1021/ol400035f