4612-64-0Relevant articles and documents
Unexpected coupling reaction of 9-lithiobromomethylene-9H-fluorene with 6,6-dicyclopropylfulvene
Paul, Gitendra C.,Gajewski, Joseph J.
, p. 524 - 526 (1997)
Metallation of 9-bis(bromomethylene)-9H-fluorene with one equivalent of BuLi at -78°C followed by quenching with 6,6-dicyclopropylfulvene and subsequent warming (room temperature, 18 h) gave an adduct identified as compound 5 (~ 70% yield). Under identical conditions dimethylfulvene and cyclopropylmethylfulvene failed to give a similar adduct. Simple and efficient syntheses of 9-bromomethylene- and 9-bis(bromomethylene)-9H- fluorene are also described.
A new class of singlet carbene ligands
Alcarazo, Manuel,Suarez, Rosa M.,Goddard, Richard,Fuerstner, Alois
, p. 9746 - 9749 (2010)
(Figure Presented) What are you? Deprotonation of fluorenylidene phosphonium salts generates reactive intermediates that can be described as push-pull cumulenes or singlet carbenes (see scheme). Whereas the NMR data are ambiguous, the coordination behavior shows the ready availability of a lone pair at the central C atom. The donor ability of singlet carbene ligands of this new class exceeds that of the commonly used N-heterocyclic carbenes (NHCs).
Alumina-Mediated π-Activation of Alkynes
Akhmetov, Vladimir,Amsharov, Konstantin,Feofanov, Mikhail,Sharapa, Dmitry I.
, 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.
