6796-35-6Relevant academic research and scientific papers
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.
Iron-catalyzed regioselective cyclotrimerization of alkynes to benzenes
Gawali, Suhas Shahaji,Gunanathan, Chidambaram
, p. 139 - 149 (2019/01/03)
We report the synthesis and characterization of simple di(aminomethyl)pyridine ligated iron-pincer complexes, which catalyzed the regioselective [2+2+2] cyclotrimerization of terminal aryl and alkyl alkynes to provide the 1,2,4-trisubstituted benzene molecules. Interestingly, internal alkynes also exhibited similar cyclization and resulted in hexa-substituted benzene compounds. Increased steric bulk on pincer ligands diminished the selectivity for cycloaddition. Cyclotrimerization reactions proceeded at room temperature upon activation of catalyst by a Grignard reagent. EPR studies indicated thermally induced spin crossover effect in catalyst.
Can the Ti(OiPr)4/nBuLi combination of reagents function as a catalyst for [2+2+2] alkyne cyclotrimerisation reactions?
Siemiaszko, Gabriela,Six, Yvan
supporting information, p. 20219 - 20226 (2018/12/13)
Catalysis of the cyclotrimerisation of alkynes with the Ti(OiPr)4/nBuLi system was studied, leading to the development of a particularly convenient and reliable protocol. This method allows the [2+2+2] cycloaddition reaction to proceed within a few minutes under microwave conditions, with generally good selectivity from a variety of aromatic and aliphatic alkynes.
Silica-supported tungsten carbynes (≡SiO)xW(≡CH)(Me)y (x = 1, y = 2; X = 2, y = 1): New efficient catalysts for alkyne cyclotrimerization
Riache, Nassima,Dery, Alexandre,Callens, Emmanuel,Poater, Albert,Samantaray, Manoja,Dey, Raju,Cavallo, Luigi,Basset, Jean-Marie,Hong, Jinhua,Li, Kun
, p. 690 - 695 (2015/06/01)
The activity of silica-supported tungsten carbyne complexes (≡SiO)xW(≡CH)(Me)y (x = 1, y = 2; x = 2, y = 1) toward alkynes is reported. We found that they are efficient precatalysts for terminal alkyne cyclotrimerization with high TONs. We also demonstrate that this catalyst species is active for alkyne cyclotrimerization without the formation of significant alkyne metathesis products. Additional DFT calculations highlight the importance of the W coordination sphere in supporting this experimental behavior.
Ti(OiPr)4/nBuLi: An attractive reagent system for [2+2+2] cyclotrimerisation reactions
Rassadin,Nicolas,Six
supporting information, p. 7666 - 7669 (2014/07/08)
A convenient method for the [2+2+2] cyclotrimerisation of alkynes using Ti(OiPr)4/nBuLi is presented. Homotrimerisation of arylacetylenes proceeds within minutes with excellent regioselectivity. Moreover, the intermolecular construction of ABB heterotrimers can be achieved selectively from two different alkynes with similar electronic properties. The method is also suitable for the synthesis of pyridines.
Exploiting guanidine as a ligand in cobalt-catalyzed alkyne cyclotrimerizations
Eichman, Chad C.,Bragdon, Jason P.,Stambuli, James P.
supporting information; experimental part, p. 1109 - 1112 (2011/06/20)
The synthesis of polysubstituted arenes is accomplished via the regioselective cyclotrimerization of alkynes utilizing a guanidine-ligated cobalt catalyst. Georg Thieme Verlag Stuttgart - New York.
