Toward Perfect Regiocontrol for β-Selective Cyclopolymerization Using a Ru-Based Olefin Metathesis Catalyst
Abstract
Ru-based metathesis catalysts employed in cyclopolymerization (CP) of 1,6-heptadiyne derivatives have promoted regioselective α-addition to alkynes, forming various conjugated polyenes containing exclusively five-membered repeat units. Recently, we discovered that a new chelated Ru catalyst could promote regioselective β-addition to produce analogous polyenes containing six-membered rings with moderate to good β-selectivity. Since then, we have focused our research on pursuing more active and β-selective regiocontrol to produce conjugated polymers with excellent β-selectivity, with a much broader range of monomers. Herein, we demonstrate highly β-selective CP by combining a new dithiolate-chelated Ru-based catalyst with weakly coordinating pyridine additives, which significantly enhance the conversion and β-selectivity. An in-depth mechanistic investigation by ^1H NMR revealed a prominent role for the additives, which improve the stability of the propagating carbene.
Additional Information
© 2018 American Chemical Society. Received: May 6, 2018; Revised: May 28, 2018; Published: June 7, 2018. The financial support from Creative Research Initiative Program and the Nano-Material Technology Development Program through NRF is acknowledged. K.K. is supported by NRF-Global Ph.D. Fellowship program (Grant NRF-2015H1A2A1033766). We thank NCIRF and NICEM at SNU for supporting ^(13)C NMR experiments and LINC at Sogang University for supporting HR-MS experiments. The authors declare no competing financial interest.Attached Files
Supplemental Material - ma8b00969_si_001.pdf
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Additional details
- Eprint ID
- 86914
- DOI
- 10.1021/acs.macromol.8b00969
- Resolver ID
- CaltechAUTHORS:20180608-101413686
- NRF-2015H1A2A1033766
- National Research Foundation of Korea
- Created
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2018-06-08Created from EPrint's datestamp field
- Updated
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2021-11-15Created from EPrint's last_modified field