A process for forming an ene reaction product wherein an enophile, such as maleic anhydride, is reacted with reactive polyalkene having a terminal vinylidene content of at least 30 mol. %, at high temperature in the presence of a free radical inhibitor. The polyalkenyl acylating agents are useful per se as additives in lubricating oils, functional fluids, and fuels and also serve as intermediates in the preparation of other products (e.g., succinimides) useful as additives in lubricating oils, functional fluids, and fuels. The presence of the free radical inhibitor during the high temperature reaction results in a reaction product that is low, or substantially free from sediment.