Gold-catalyzed regiospecific annulation of unsymmetrically substituted 1,5-diynes for the precise synthesis of bispentalenes
Precise control of the selectivity in organic synthesis is important to access the desired molecules. We demonstrate a regiospecific annulation of unsymmetrically substituted 1,2-di(arylethynyl)benzene derivatives for a geometry-controlled synthesis of linear bispentalenes, which is one of the promi...
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| Main Authors: | , , , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
July 16, 2019
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| In: |
Chemistry - a European journal
Year: 2019, Volume: 25, Issue: 52, Pages: 12180-12186 |
| ISSN: | 1521-3765 |
| DOI: | 10.1002/chem.201902381 |
| Online Access: | Resolving-System, Volltext: https://doi.org/10.1002/chem.201902381 Verlag: https://onlinelibrary.wiley.com/doi/10.1002/chem.201902381 
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| Author Notes: | Sara Tavakkolifard, Kohei Sekine, Lisa Reichert, Mina Ebrahimi, Ketevan Museridz, Elena Michel, Frank Rominger, Rasool Babaahmadi, Alireza Ariafard, Brian F. Yates, Matthias Rudolph, and A. Stephen K. Hashmi |
| Summary: | Precise control of the selectivity in organic synthesis is important to access the desired molecules. We demonstrate a regiospecific annulation of unsymmetrically substituted 1,2-di(arylethynyl)benzene derivatives for a geometry-controlled synthesis of linear bispentalenes, which is one of the promising structures for material science. A gold-catalyzed annulation of unsymmetrically substituted 1,2-di(arylethynyl)benzene could produce two isomeric pentalenes, but both electronic and steric effects on the aromatics at the terminal position of the alkyne prove to be crucial for the selectivity; especially a regiospecific annulation was achieved with sterically blocked substituents; namely, 2,4,6-trimetyl benzene or 2,4-dimethyl benzene. This approach enables the geometrically controlled synthesis of linear bispentalenes from 1,2,4,5-tetraethynylbenzene or 2,3,6,7-tetraethynylnaphthalene. Moreover, the annulation of a series of tetraynes with a different substitution pattern regioselectively provided the bispentalene scaffolds. A computational study revealed that this is the result of a kinetic control induced by the bulky NHC ligands. |
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| Item Description: | Version of record online: August 28, 2019 Gesehen am 07.11.2019 |
| Physical Description: | Online Resource |
| ISSN: | 1521-3765 |
| DOI: | 10.1002/chem.201902381 |