Rh(III)-Catalyzed Cyclopropanation Initiated by C-H Activation: Ligand Development Enables a Diastereoselective [2+1] Annulation of N-Enoxyphthalimides and Alkenes

N-Enoxyphthalimides undergo a Rh(III)-catalyzed C-H activation initiated cyclopropanation of electron deficient alkenes. The reaction is proposed to proceed via a directed activation of the olefinic C-H bond followed by two migratory insertions, first across the electron-deficient alkene and then by cyclization back onto the enol moiety. A newly designed isopropylcyclopentadienyl ligand drastically improves yield and diastereoselectivity.