Synlett 2024; 35(09): 983-988
DOI: 10.1055/s-0042-1751527
cluster
Chemical Synthesis and Catalysis in Germany

Remote Enantioselective Epoxidation Reactions Catalyzed by Chiral Iron Porphyrin Complexes with a Hydrogen-Bonding Site

Hussayn Ahmed
a   Technische Universität München, School of Natural Sciences Department Chemie and Catalysis Research Center (CRC), 85747 Garching, Germany
,
Alexander Pöthig
a   Technische Universität München, School of Natural Sciences Department Chemie and Catalysis Research Center (CRC), 85747 Garching, Germany
,
Khai-Nghi Truong
b   Rigaku Europe SE, Hugenottenallee 167, 63263 Neu-Isenburg, Germany
,
Thorsten Bach
a   Technische Universität München, School of Natural Sciences Department Chemie and Catalysis Research Center (CRC), 85747 Garching, Germany
› Author Affiliations
Financial support by the Deutsche Forschungsgemeinschaft (Ba 1372/23) is gratefully acknowledged.


Abstract

Iron porphyrin complexes, which were linked via a para-phenylethynyl group to a chiral scaffold with a lactam binding site, were probed as catalysts in the enantioselective epoxidation of 4-(ω-alkenyl)-quinolones. It was found that the 3-butenyl group in the substrate accounts for the highest enantioselectivity (up to 44% ee) and the absolute configuration of an oxirane product was elucidated by electron diffraction. A two-point hydrogen bond of the substrate to the catalyst is likely responsible for enantioface differentiation at a remote position. The study shows chirality transfer to be possible via four nonstereogenic carbon atoms between the binding site of the substrate and its reactive C=C double bond.

Supporting Information

Primary Data



Publication History

Received: 27 September 2023

Accepted after revision: 30 October 2023

Article published online:
30 November 2023

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