Contrary to the S-vinylation, the P-vinylation of diarylphosphine oxides 4 led exclusively to terminal alkenes 5 (Scheme 1b), and preliminary mechanistic studies revealed that a radical pathway was unlikely. Hence a ligand coupling mechanism can be ruled out, as this would lead to the internal alkene product. With inspiration from previous P-functionalizations with vinyl-34 and alkynyliodonium salts, and recent mechanistic studies with EBX, we proposed five pathways leading to terminal alkene 5a and 2-iodobenzoate (Scheme 4).