29536-28-5Relevant articles and documents
Selective cyclotrimerization of acetylenes via tantalum-alkyne complexes
Takai, Kazuhiko,Yamada, Masashi,Utimoto, Kiitiro
, p. 851 - 852 (1995)
Tantalum-alkyne complexes from internal acetylenes and low-valent tantalum (TaCl5 and Zn) in DME and benzene react with terminal diynes in presence of THF and pyridine to give tetrasubstituted benzene derivatives in good to excellent yields.
H-BPin/KOtBu Promoted Activation of Cobalt Salt to a Heterotopic Catalyst for Highly Selective Cyclotrimerization of Alkynes
Song, Shuo,Li, Chuhan,Liu, Tianfen,Zhang, Panke,Wang, Xiaoming
supporting information, p. 6925 - 6930 (2021/09/14)
A mixture of HBPin with KOtBu was found to activate cobalt salt to form a heterotopic cobalt species that is highly active for catalytic intermolecular trimerization of alkynes. This protocol affords 1,2,4-regioisomers in good yields with high regioselectivities under mild conditions. These salient features, together with the operational simplicity and high efficiency, as well as obviating the use of any costly and/or air sensitive ligands, renders the protocol promising for practical applications.
Combined Photoredox and Iron Catalysis for the Cyclotrimerization of Alkynes
Chakraborty, Uttam,Jacobi von Wangelin, Axel,Neumeier, Michael,Perez-Ruiz, Raul,Schaarschmidt, Dieter,de la Pena O'Shea, Victor
supporting information, p. 13473 - 13478 (2020/06/02)
Successful combinations of visible-light photocatalysis with metal catalysis have recently enabled the development of hitherto unknown chemical reactions. Dual mechanisms from merging metal-free photocatalysts and earth-abundant metal catalysts are still in their infancy. We report a photo-organo-iron-catalyzed cyclotrimerization of alkynes by photoredox activation of a ligand-free Fe catalyst. The reaction operates under very mild conditions (visible light, 20 °C, 1 h) with 1–2 mol percent loading of the three catalysts (dye, amine, FeCl2).