Reversible Cleavage/Formation of the Chromium-Chromium Quintuple Bond in the Highly Regioselective Alkyne Cyclotrimerization
| Autor: | Jen-Shiang K. Yu, Yi-Chou Tsai, Yu Siang Huang, Yao Lun Liu, Gou Tao Huang |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
010405 organic chemistry Chemistry Stereochemistry Alkyne chemistry.chemical_element Regioselectivity Homogeneous catalysis General Medicine General Chemistry 010402 general chemistry 01 natural sciences Medicinal chemistry Catalysis 0104 chemical sciences chemistry.chemical_compound Chromium Quintuple bond |
| Zdroj: | Angewandte Chemie International Edition. 56:15427-15431 |
| ISSN: | 1433-7851 |
| DOI: | 10.1002/anie.201709583 |
| Popis: | Here we report the employment of the quintuply bonded dichromium amidinates [Cr{κ2-HC(N-2,6-iPr2C6H3)(N-2,6-R2C6H3)}]2 (R = iPr (1), Me (7)) as catalysts to mediate the [2+2+2] cyclotrimerization of terminal alkynes giving 1,3,5-trisubstituted benzenes. During the catalysis, the ultrashort Cr-Cr quintuple bond underwent reversible cleavage/formation, corroborated by the characterization of two inverted arene sandwich dichromium complexes (μ-η6:η6-1,3,5-(Me3Si)3C6H3)[Cr{κ2-HC(N-2,6-iPr2C6H3)(N-2,6-R2C6H3)}]2 (R = iPr (5), Me (8)). In the presence of σ donors such as THF and 2,4,6-Me3C6H2CN, the bridging arene 1,3,5-(Me3Si)3C6H3 in 5 and 8 was extruded and 1 and 7 were regenerated. Theoretical calculations were employed to disclose the reaction pathways of these highly regioselective [2+2+2] cylcotrimerization reactions of terminal alkynes. |
| Databáze: | OpenAIRE |
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