120819-22-9Relevant academic research and scientific papers
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.
Evaluating the Effect of Catalyst Nuclearity in Ni-Catalyzed Alkyne Cyclotrimerizations
Pal, Sudipta,Uyeda, Christopher
supporting information, p. 8042 - 8045 (2015/07/15)
An evaluation of catalyst nuclearity effects in Ni-catalyzed alkyne oligomerization reactions is presented. A dinuclear complex, featuring a Ni-Ni bond supported by a naphthyridine-diimine (NDI) ligand, promotes rapid and selective cyclotrimerization to form 1,2,4-substituted arene products. Mononickel congeners bearing related N-donor chelates (2-iminopyridines, 2,2′-bipyridines, or 1,4,-diazadienes) are significantly less active and yield complex product mixtures. Stoichiometric reactions of the dinickel catalyst with hindered silyl acetylenes enable characterization of the alkyne complex and the metallacycle that are implicated as catalytic intermediates. Based on these experiments and supporting DFT calculations, the role of the dinuclear active site in promoting regioselective alkyne coupling is discussed. Together, these results demonstrate the utility of exploring nuclearity as a parameter for catalyst optimization.
Synthesis of symmetrical and unsymmetrical trisubstituted benzene derivatives through ring-closing alkyne metathesis strategy and dcpropargylation with various catalysts
Kotha, Sambasivarao,Bansal, Dccpti,Kumar, Ramanatham Vinod
experimental part, p. 225 - 230 (2009/12/03)
Alkync trimerizalion by application of the Grubbs ruthenium first generation catalyst has been demonstrated. In this regard, triaryloxymethylbenzene derivatives have been generated by co- trimerization of propargylated phenol derivatives with the aid of the Grubbs catalyst. Depropargylation under various catalysts have been studied.
