Stierle, Max and Jaschke, Constantin and Grenda, Daniel J. and Peschel, Martin T. and Pickl, Thomas and Gessner, Niklas and Nuernberger, Patrick and Fingerhut, Benjamin P. and Ochsenfeld, Christian and de Vivie-Riedle, Regina and Bach, Thorsten (2025) Enantioselective Photochemical Generation of a Short-Lived, Twisted Cycloheptenone Isomer: Catalytic Formation, Detection, and Consecutive Chemistry. ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 64 (23): e202501433. ISSN 1433-7851, 1521-3773
Full text not available from this repository. (Request a copy)Abstract
Cyclohept-2-enone-3-carboxylic acid undergoes a photochemical isomerization from its cis- to its trans-form either upon direct irradiation (lambda = 366 nm) or in the presence of a triplet sensitizer (lambda = 459 nm). The intermediate chiral trans-isomer was detected by step-scan FTIR, displaying a lifetime of 130 mu s (r.t., CH2Cl2). Ensuing Diels-Alder reactions of the trans-isomer occurred smoothly and produced chiral trans-fused cycloaddition products (14 examples, 24%-98% yield). Benzylation led to esters, which were separated by chiral HPLC and which were employed to evaluate a possible enantioselective reaction course. It was discovered that a chiral phosphoric acid with a pendant sensitizing group induces a notable enantioselectivity in the photoisomerization step. The planar chirality of the trans-cycloheptene translates into point chirality in the Diels-Alder reaction (seven examples, up to 38% ee). Computational studies suggest that the chiral conformation of the cis-isomer adopted within the assembly to the chiral phosphoric acid induces the enantioselectivity in a one-bond flip (OBF) toward the trans-isomer. Trajectory surface hopping (TSH) simulations showed exemplarily how a chiral trans-cyclohept-2-enone is formed from a chiral cis-conformer. For the Diels-Alder reaction, a weak ground state selectivity was found to attenuate the enantioselectivity achieved in the photochemical step.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | DIELS-ALDER REACTIONS; 2+2 PHOTOCYCLOADDITION; PHOSPHORIC-ACID; CIS; PHOTOISOMERIZATION; ORGANOCATALYSIS; CYCLOADDITIONS; ISOMERIZATION; SENSITIZATION; INTERMEDIATE; Computational chemistry; Cycloaddition; Enantioselectivity; Isomerization; Photochemistry |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Physical Chemistry I > Prof. Dr. Patrick Nürnberger |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 02 Jun 2026 11:34 |
| Last Modified: | 02 Jun 2026 11:34 |
| URI: | https://pred.uni-regensburg.de/id/eprint/67392 |
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