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Designing ‘Totem’ C 2 ‐Symmetrical Iron Porphyrin Catalysts for Stereoselective Cyclopropanations
Author(s) -
Carminati Daniela Maria,
Intrieri Daniela,
Caselli Alessandro,
Le Gac Stéphane,
Boitrel Bernard,
Toma Lucio,
Legnani Laura,
Gallo Emma
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201602289
Subject(s) - cyclopropanation , porphyrin , catalysis , carbene , stereoselectivity , diazo , alkene , chemistry , ligand (biochemistry) , cycloalkane , stereochemistry , photochemistry , medicinal chemistry , organic chemistry , biochemistry , receptor
The catalytic activity of the iron(III) C 2 chiral 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.