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Gold-Catalyzed Oxidative Coupling of Alkynes toward the Synthesis of Cyclic Conjugated Diynes
Gold-catalyzed oxidative coupling of alkynes was developed as an efficient approach for the synthesis of challenging cyclic conjugated diynes (CCD). Compared with the classic copper-promoted oxidative coupling reaction of alkynes, this gold-catalyzed process exhibited a faster reaction rate due to r...
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| Published in: | Chem 2018-08, Vol.4 (8), p.1983-1993 |
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| Main Authors: | , , , , , |
| Format: | Article |
| Language: | English |
| Subjects: | |
| Citations: | Items that this one cites Items that cite this one |
| Online Access: | Request full text |
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| Summary: | Gold-catalyzed oxidative coupling of alkynes was developed as an efficient approach for the synthesis of challenging cyclic conjugated diynes (CCD). Compared with the classic copper-promoted oxidative coupling reaction of alkynes, this gold-catalyzed process exhibited a faster reaction rate due to rapid reductive elimination from the Au(III) intermediate. This unique reactivity thus allowed a challenging diyne macrocyclization to take place with high efficiency. Condition screening revealed an [(n-Bu)4N]+[Cl-Au-Cl]− salt as the optimal pre-catalyst. Macrocycles with ring size between 13 and 28 atoms were prepared in moderate to good yields, which highlighted the broad substrate scope of this new strategy. Furthermore, the synthetic utilities of the CCDs for copper-free click chemistry have been demonstrated, showcasing the potential application of this strategy in biological systems.
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•First synthesis of challenging cyclic conjugated diynes via gold catalysis•[(n-Bu)4N]+[Cl-Au-Cl]− salt as a pre-catalyst toward gold redox chemistry•Facile access to functionalized cyclic conjugated diynes with 13–28 member rings•Copper-free azide-alkyne cycloaddition for potential biological research
Macrocycles are important structural moieties in medicinal and biological research, and efficient methods for macrocyclization are always in high demand. With the unique conformation having six carbon atoms in a linear geometry, the cyclic conjugated diynes (CCD) present greater synthetic challenges and have been much less explored. Therefore, application of these unique macrocycles in biological studies is largely unexplored. Here, we describe the discovery of gold-catalyzed Glaser-Hay type oxidative coupling of terminal alkynes to achieve CCD under diluted conditions with broad substrate scope and great functional group compatibility. Taking advantage of the 14-member cyclic diyne, a copper-free click chemistry was achieved, which provided an effective alternative strategy for the traditional cyclooctyne-based azide-alkyne cycloaddition, suggesting a promising future for this method in tackling challenging problems in related biological and medicinal research.
Gold-catalyzed oxidative coupling of alkynes was developed as an efficient approach for the synthesis of challenging cyclic conjugated diyne. Compared with copper-promoted oxidative coupling, this protocol allowed macrocyclization under dilute conditions with good overall reactivity and high functional |
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| ISSN: | 2451-9294 2451-9294 |
| DOI: | 10.1016/j.chempr.2018.07.004 |