Rh(III)-Catalyzed Cyclopropanation Initiated by C-H Activation: Ligand Development Enables a Diastereoselective [2 + 1] Annulation of N-Enoxyphthalimides and Alkenes
Tiffany Piou and Tomislav Rovis*
*Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States, Email: rovislamar.colostate.edu
T. Piou, T. Rovis, J. Am. Chem. Soc., 2014, 136, 11292-11295.
DOI: 10.1021/ja506579t (free Supporting Information)
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A Rh(III) catalyst promotes a cyclopropanation of electron deficient alkenes with N-Enoxyphthalimides 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.
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