221230-46-2Relevant academic research and scientific papers
Alkynes as Linchpins for the Additive Annulation of Biphenyls: Convergent Construction of Functionalized Fused Helicenes
Mohamed, Rana K.,Mondal, Sayantan,Guerrera, Joseph V.,Eaton, Teresa M.,Albrecht-Schmitt, Thomas E.,Shatruk, Michael,Alabugin, Igor V.
, p. 12054 - 12058 (2016)
A new approach to fused helicenes is reported, where varied substituents are readily incorporated in the extended aromatic frame. From the alkynyl precursor, the final helical compounds are obtained under mild conditions in a two-step process, in which th
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.
Copper-catalyzed cascade annulation between α-bromocarbonyls and biaryl or (: Z)-arylvinylacetylenes enabling a direct synthesis of dibenzocycloheptanes and related compounds
Lu, Danyang,Wan, Yimei,Kong, Lichun,Zhu, Gangguo
supporting information, p. 13971 - 13974 (2016/12/09)
Copper-catalyzed cascade annulation of γ,δ-unsaturated α-bromocarbonyls with biaryl or (Z)-arylvinylacetylenes is presented, giving an expeditious access to dibenzocycloheptanes and related compounds in moderate to high yields. It provides a novel method for the one-pot synthesis of cycloheptane and cycloheptene-fused polycyclic scaffolds featuring a rare 7-endo-trig radical cyclization.
Synthesis of 4-alkylidene-substituted 1,2,3,4-tetrahydroisoquinolines via palladium-catalyzed carbopalladation/C-H activation of 2-bromobenzyl-N-propargylamines
Naveen, Kanagaraj,Nandakumar, Avanashiappan,Perumal, Paramasivan Thirumalai
, p. 1633 - 1642 (2015/03/31)
Abstract Tetrasubstituted alkene-based 1,2,3,4-tetrahydroisoquinolines are synthesized via the formation of a cyclic carbopalladation complex followed by C-H bond activation of the sp2 carbon in arenes. This domino reaction proceeds with good selectivity and provides good yields of the products. The requisite starting materials are synthesized by copper(I) iodide catalyzed A3-coupling reactions.
Flexible synthesis of phenanthrenes by a PtCl2-catalyzed cycloisomerization reaction
Fuerstner, Alois,Mamane, Victor
, p. 6264 - 6267 (2007/10/03)
Readily available biphenyl derivatives containing an alkyne unit at one of their ortho positions are converted into substituted phenanthrenes upon exposure to catalytic amounts of either PtCl2, AuCl3, GaCl3, or InCl3 in toluene. This 6-endo-dig cyclization likely proceeds through initial π-coordination of the alkyne unit followed by interception of the resulting η2-metal complex by the adjacent arene ring. The reaction is inherently modular, allowing for substantial structural variations and for the incorporation of substituents at any site of the phenanthrene product except C-9. Moreover, the reaction is readily applied to the heterocyclic series as exemplified by the preparation of benzoindoles, naphthothiophenes as well as bridgehead nitrogen hetero- cycles.
