70486-08-7Relevant academic research and scientific papers
Alumina-Mediated π-Activation of Alkynes
Akhmetov, Vladimir,Amsharov, Konstantin,Feofanov, Mikhail,Sharapa, Dmitry I.
supporting information, p. 15420 - 15426 (2021/09/30)
The ability to induce powerful atom-economic transformation of alkynes is the key feature of carbophilic π-Lewis acids such as gold- and platinum-based catalysts. The unique catalytic activity of these compounds in electrophilic activations of alkynes is explained through relativistic effects, enabling efficient orbital overlapping with π-systems. For this reason, it is believed that noble metals are indispensable components in the catalysis of such reactions. In this study, we report that thermally activated γ-Al2O3activates enynes, diynes, and arene-ynes in a manner enabling reactions that were typically assigned to the softest π-Lewis acids, while some were known to be triggered exclusively by gold catalysts. We demonstrate the scope of these transformations and suggest a qualitative explanation of this phenomenon based on the Dewar-Chatt-Duncanson model confirmed by density functional theory calculations.
Rh(II)-Catalyzed Alkynylcyclopropanation of Alkenes by Decarbenation of Alkynylcycloheptatrienes
Echavarren, Antonio M.,Mato, Mauro,Montesinos-Magraner, Marc,Sugranyes, Arnau R.
supporting information, p. 10760 - 10769 (2021/07/28)
Alkynylcyclopropanes have found promising applications in both organic synthesis and medicinal chemistry but remain rather underexplored due to the challenges associated with their preparation. We describe a convenient two-step methodology for the alkynyl
Synthesis of Barbaralones and Bullvalenes Made Easy by Gold Catalysis
Ferrer, Sofia,Echavarren, Antonio M.
supporting information, p. 11178 - 11182 (2016/10/13)
The gold(I)-catalyzed oxidative cyclization of 7-ethynyl-1,3,5-cycloheptatrienes gives 1-substituted barbaralones in a general manner, which simplifies the access to other fluxional molecules. As an example, we report the shortest syntheses of bullvalene, phenylbullvalene, and disubstituted bullvalenes, and a readily accessible route to complex cage-type structures by further gold(I)-catalyzed reactions.
Gold for the generation and control of fluxional barbaralyl cations
McGonigal, Paul R.,De Leon, Claudia,Wang, Yahui,Homs, Anna,Solorio-Alvarado, Cesar R.,Echavarren, Antonio M.
supporting information, p. 13093 - 13096 (2013/03/13)
Fluxional molecules which rapidly pass back and forth between a large number of constitutional isomers through low-energy rearrangements have fascinated chemists owing to their role in the study of fundamental theoretical concepts[ 2] and their potential to adapt their chemical structures in response to their environment or to act as prototypical molecular transport systems. They represent a facet of systems chemistry that is relatively unexplored, in which a dynamic structural library can be contained within a single molecule. The 9-barbaralyl cation (1) is a hugely fluxional C9H9 + hydrocarbon that exists as a mixture of 181 400 degenerate forms which interconvert rapidly at temperatures as low as -135 °C-each carbon atom may exchange with every other carbon atom in the structure through a series of pericyclic reactions. Unlike the neutral homologues semibullvalene (2; two degenerate tautomers) and bullvalene (3; 1209600 degenerate tautomers), which are stable compounds under ambient conditions, 1 is highly reactive and undergoes irreversible rearrangement to 1,4-bishomotropylium cation (4) above -125 °C. Functionalized barbaralanes may be suitable candidates for switchable, fluxional molecules. However, the difficulty in handling these compounds coupled with the low-yielding, multistep syntheses and harsh reaction conditions (typically featuring strongly or super acidic media) employed in the generation of 1 and its derivatives have so far limited the extent to which the chemistry of this fascinating dynamic carbon skeleton has been explored.
Preparation of 7-alkylcyclohepta-1,3,5-trienes from organometallics and either tropylium tetrafluoroborate or 7-ethoxycyclohepta-1,3,5-triene
Picotin, G.,Faye, A.,Miginiac, P.
, p. 245 - 251 (2007/10/02)
The reaction of several organolithium compounds and the reaction of α-unsaturated organozinc and organoaluminium compounds with either the readily prepared tropylium tetrafluoroborate or with 7-ethoxycyclohepta-1,3,5-triene give the corresponding 7-alkylcyclohepta-1,3,5-trienes.On the other hand, with organomagnesium compounds, only 7-ethoxycyclohepta-1,3,5-triene gives the expected 7-alkylcyclohepta-1,3,5-trienes while the reaction of tropylium tetrafluoroborate is abnormal.
