%0 Journal Article %1 stockl2022chasing %A Stöckl, Yannick %A Fellmeth, Thomas %A Bauer, Florian %A Wank, Bianca %A Frey, Wolfgang %A Claasen, Birgit %A Zens, Anna %A Köhn, Andreas %A Laschat, Sabine %D 2022 %J Eur. J. Org. Chem. %K chemie koehn köhn myown stuttgart theoretische %N 26 %P e202101416 %R 10.1002/ejoc.202101416 %T Chasing Polycyclic Natural Products: 5/6/5- or 5/6/6-Carbotricyclic Scaffold Construction via Stereodivergent Diels-Alder Reaction of Chiral Hydrindanes and Their Boron Complexes %U https://dx.doi.org/10.1002/ejoc.202101416 %V 2022

@article{stockl2022chasing, abstractnote = {Chiral trans-hydrindanes (bicyclo[4.3.0]nonanes) are important building blocks of polycyclic natural products. In order to access 5/6/5- and 5/6/6-carbotricyclic scaffolds scope and limitation of [4+2] cycloadditions of tetrahydroindanones with various dienes were studied. Cyclopentadiene gave a tetracylic endo-(R,R)-diastereomer under acid-catalysis, whereas thermal conditions provided the endo-(S,S)-diastereomer with the opposite diastereofacial selectivity. The stereodivergent outcome was rationalized by high-level quantum-chemical computations which revealed the acid-catalysis to be a kinetically controlled reaction and the thermal cycloaddition to be under thermodynamic control. Stereochemical assignment of the cycloadducts was facilitated by conversion of the 1,3-dicarbonyls with BF3 ⋅ OEt2 into BF2-chelate complexes. Subsequent thermal Diels-Alder reaction of BF2- or BBN-chelates (from 9-BBN-OTf) gave endo/exo-mixtures of the (R,R)- and (S,S)-diastereomers, while more elevated temperatures yielded primarily the endo/exo-(S,S)-diastereomers. Thermal [4+2] cycloadditions with 2,3-dimethylbutadiene proceeded with lower diastereoselectivity as the reaction was kinetically controlled according to calculations. Attempted Diels-Alder-reactions with furan gave furyl-substituted indanones rather than cycloadducts. The Diels-Alder reaction of 4-substituted tetrahydroindanones with cyclic and acyclic dienes was examined. By choosing acidic or thermal conditions, the diastereoselectivity on the newly formed ring could be controlled and was rationalized by high-level computations. Additionally, boron complexation of the 1,3-dicarbonyl moiety exhibited unexpected selectivity in the cycloaddition.}, added-at = {2022-11-09T17:02:45.000+0100}, author = {Stöckl, Yannick and Fellmeth, Thomas and Bauer, Florian and Wank, Bianca and Frey, Wolfgang and Claasen, Birgit and Zens, Anna and Köhn, Andreas and Laschat, Sabine}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/255f34e7401b19d3c3ef66fb3a50a252f/akoehn}, doi = {10.1002/ejoc.202101416}, interhash = {3ea240631f16b90996a43b0978bc1b70}, intrahash = {55f34e7401b19d3c3ef66fb3a50a252f}, issn = {1434-193X}, journal = {Eur. J. Org. Chem.}, keywords = {chemie koehn köhn myown stuttgart theoretische}, number = 26, pages = {e202101416}, timestamp = {2022-11-09T16:02:45.000+0100}, title = {Chasing Polycyclic Natural Products: 5/6/5- or 5/6/6-Carbotricyclic Scaffold Construction via Stereodivergent Diels-Alder Reaction of Chiral Hydrindanes and Their Boron Complexes}, url = {https://dx.doi.org/10.1002/ejoc.202101416}, volume = 2022, year = 2022 }