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Highly Diastereoselective Cyclopropanation of Olefins Catalysed By a C2-Symmetrical Chiral Iron Porphyrin Complex

Monday, May 12, 2014: 14:40
Bonnet Creek Ballroom X, Lobby Level (Hilton Orlando Bonnet Creek)
E. Gallo, D. Intrieri (Dipartimento di Chimica, UniversitÓ degli Studi di Milano), S. Le Gac (Institut des Sciences Chimiques de Rennes, UMR CNRS 6226, UniversitÚ de Rennes 1), A. Caselli (Dipartimento di Chimica, UniversitÓ degli Studi di Milano), E. Rose (UniversitÚ P. et M. Curie, UPMC Paris 06, IPCM, UMR CNRS 7201), and B. Boitrel (Institut des Sciences Chimiques de Rennes, UMR CNRS 6226, UniversitÚ de Rennes 1)
Compounds containing cyclopropane units play a crucial role in both synthetic and pharmaceutical chemistry due to high reactivity and biological properties of the three-membered ring.[1] Consequently, the interest of the research community in developing new methodologies to synthesise cyclopropanes is strongly increasing. Amongst the synthetic procedures available, the one-pot reaction of diazo compounds with olefins is a sustainable and atom-efficient strategy due to the formation of N2as the only stoichiometric by product.

Catalytic enantio- and diasteroselective olefin cyclopropanations [2] have been extensively explored and metal porphyrin complexes represent a very active and stereoselective class of catalysts. Some years ago we reported on the catalytic efficiency of chiral cobalt(II)-binaphthyl porphyrins in asymmetric cyclopropanations, [3] and recorded positive data encouraging us to synthesise the structurally related chiral porphyrin 1 and its iron(III) complex 2 (see figure). The catalytic activity of 2 in the asymmetric cyclopropanation of olefins by diazo compounds was investigated. Cyclopropanes were obtained with excellent yields (up to 99%), enantio- and diasteroselectivities (eetrans up to 80%, cis/trans ratios up to 99%). In addition to that, outstanding values of TON and TOF (20,000 and 120,000/h respectively) were achieved. [4]

References

[1] A. K. Kumar, Intern. J. Pharm. and Pharm. Sci. 2013, 5, 467-472.

[2] D. Intrieri, A. Caselli and E. Gallo, Eur. J. Inorg. Chem. 2011, 5071-5081.

[3] (a) S. Fantauzzi, E. Gallo, E. Rose, N. Raoul, A. Caselli, S. Issa, F. Ragaini and S. Cenini, Organometallics, 2008, 27, 6143-6151. (b) A. Penoni, R. Wanke, S. Tollari, E. Gallo, D. Musella, F. Ragaini, F. Demartin and S. Cenini, Eur. J. Inorg. Chem. 2003, 1452-1460.

[4] D. Intrieri, S. Le Gac, A. Caselli, E. Rose, B. Boitrel and E. Gallo submitted