Base-Promoted Aryl Carbon–Iodine and Carbon–Bromine Bond Cleavage with Rhodium Porphyrin Complexes: Scope and Mechanism

Base-promoted aryl carbon–iodine and carbon–bromine bond (Ar–X, X = I, Br) cleavage by rhodium porphyrin complexes was achieved to give the rhodium­(III) porphyrin aryls Rh­(ttp)Ar (ttp = tetra-p-tolylporphyrinato dianion). Mechanistic studies showed that RhII2(ttp)2 is the intermediate for Ar–X (X = I, Br) cleavage. The Ar–X cleavage process goes through a rhodium­(II) porphyrin radical mediated ipso-substitution mechanism.