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

摘要

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.