445262-78-2Relevant academic research and scientific papers
Br?nsted Acid-Catalyzed Carbocyclization of 2-Alkynyl Biaryls
Gicquiaud, Julien,Hac?hasano?lu, Antoine,Hermange, Philippe,Sotiropoulos, Jean-Marc,Toullec, Patrick Y.
supporting information, p. 2025 - 2030 (2019/03/28)
Ortho-alkynyl biaryls react in the presence of catalytic amount of Br?nsted acids to give phenanthrenes in high yields under mild conditions. The activity and selectivity of this transformation are governed by the substitution pattern of the diarylalkyne moiety. Selectivity shifts are observed between the carbophilic Lewis and Br?nsted acid-catalyzed cycloisomerization involving alkyne activation. (Figure presented.).
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.
