Abstract: | Fast I/Sm and Br/Sm exchanges take place when various aromatic or heterocyclic iodides and bromides are treated with nBu2SmCl?4 LiCl and nBu3Sm?5 LiCl, respectively. The resulting organosamarium reagents were efficiently quenched with aldehydes, ketones, and imines. Also, they undergo acylations when treated with N,N‐dimethylamides leading to ketones. The rate of the Br/Sm exchange for a typical aryl bromide was determined and found to be 8.5×105 faster than the Br/Mg exchange, indicating that the rate of a metal‐exchange is related to the ionic character of the carbon–metal bond and to the metal electronegativity. |