The catalytic activity of the iron(III) C2chiral porphyrin Fe(2)(OMe) in alkene cyclopropanation is herein reported. The catalyst promoted the reaction of differently substituted styrenes with diazo derivatives with trans-diastereoselectivities and enantioselectivities up to 99:1 and 87 %, respectively. In addition, high TON and TOF values (up to 10 000 and 120 000 h−1, respectively) were observed indicating good activity and stability of the catalyst in optimized experimental conditions. The study of the cyclopropanation reaction revealed that the porphyrin skeleton is composed of two ‘totem’ parts which were independently responsible for the observed enantio- and diastereoselectivities. To further our research we also investigated the catalytic role of the methoxy axial ligand coordinated to the iron atom. The molecular structure of Fe(2)(OMe) was optimized by DFT calculations which were also employed to achieve a better understanding of the mechanistic details of the carbene transfer reaction.

Designing ‘Totem’ C2-Symmetrical Iron Porphyrin Catalysts for Stereoselective Cyclopropanations / D.M. Carminati, D. Intrieri, A. Caselli, S. Le Gac, B. Boitrel, L. Toma, L. Legnani, E. Gallo. - In: CHEMISTRY-A EUROPEAN JOURNAL. - ISSN 0947-6539. - 22:38(2016 Aug 24), pp. 13599-13612.

Designing ‘Totem’ C2-Symmetrical Iron Porphyrin Catalysts for Stereoselective Cyclopropanations

D.M. Carminati
Primo
;
D. Intrieri
Secondo
;
A. Caselli;E. Gallo
Ultimo
2016

Abstract

The catalytic activity of the iron(III) C2chiral porphyrin Fe(2)(OMe) in alkene cyclopropanation is herein reported. The catalyst promoted the reaction of differently substituted styrenes with diazo derivatives with trans-diastereoselectivities and enantioselectivities up to 99:1 and 87 %, respectively. In addition, high TON and TOF values (up to 10 000 and 120 000 h−1, respectively) were observed indicating good activity and stability of the catalyst in optimized experimental conditions. The study of the cyclopropanation reaction revealed that the porphyrin skeleton is composed of two ‘totem’ parts which were independently responsible for the observed enantio- and diastereoselectivities. To further our research we also investigated the catalytic role of the methoxy axial ligand coordinated to the iron atom. The molecular structure of Fe(2)(OMe) was optimized by DFT calculations which were also employed to achieve a better understanding of the mechanistic details of the carbene transfer reaction.
cyclopropanation; density functional calculations; iron; porphyrins; stereoselective reactions; chemistry (all)
Settore CHIM/03 - Chimica Generale e Inorganica
24-ago-2016
Article (author)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/457336
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