56670-87-2Relevant academic research and scientific papers
Br?nsted/Lewis Acid-Promoted Site-Selective Intramolecular Cycloisomerizations of Aryl-Fused 1,6-Diyn-3-ones for Diversity-Oriented Synthesis of Benzo-Fused Fluorenes and Fluorenones and Naphthyl Ketones
Mandal, Mou,Sakthivel, Shanmugam,Balamurugan, Rengarajan
, p. 333 - 351 (2020/12/22)
Herein, a facile diversity-oriented approach to access functionalized benzo[a]fluorenes, benzo[b]fluorenones, and naphthyl ketones has been demonstrated via site-selective intramolecular cyclization of aryl-fused 1,6-diyn-3-ones. Synthesis of benzo[a]fluorenes and naphthyl ketones has been achieved selectively using TfOH and AgBF4, respectively, via in situ-formed acetals. Aryl-fused 1,6-diyn-3-ones undergo triflic acid-mediated intramolecular cyclization, leading to benzo[b]fluorenone derivatives via a radical intermediate as supported by EPR studies. Kinetic studies of these transformations have also been performed by UV-visible spectroscopic analysis to shed light on the reaction profile.
Intramolecular [4 + 2] Cycloaddition Reactions of Diarylacetylenes: Synthesis of Benzo[b]fluorene Derivatives via Cyclic Allenes
Rodríguez, David,Navarro, Armando,Castedo, Luis,Domínguez, Domingo,Saá, Carlos
, p. 1497 - 1500 (2007/10/03)
(Equation Presented) 2-Propynyldiarylacetylenes undergo thermal intramolecular [4 + 2] cycloaddition to give benzo[b]fluorene derivatives in good yields. The hybridization of the tether connecting the reacting alkynes has a pronounced effect on the course
Benzo[b]fluorenes formed in the thermal cyclization of 3-ene-1,6-diynes
Schmittel, Michael,Strittmatter, Marc,Schenk, Wolfdieter A.,Hagel, Michael
, p. 1015 - 1020 (2007/10/03)
A three-step preparation of the benzofluorene core is presented. The last step involves thermal cyclization of 3-ene-1,6-diyne (7) leading to the formation of four benzofluorene derivatives, one of which has been investigated by X-ray analysis. The harsh thermal conditions indicate that the cyclization of 7 might not proceed via a biradical intermediate as would be anticipated by a mechanistic proposal from Ueda.
Thermolysis of 2-Benzylidenebenzocyclobutenols
Bradley, Jean-Claude,Durst, Tony,Williams, A. J.
, p. 6575 - 6579 (2007/10/02)
The thermolysis of a series of 2-benzylidenebenzocyclobuten-1-ols has been studied.Whenever comparisons can be made, the rate of opening of the benzocyclobutene ring was slower for these compounds than the corresponding 2-ones.The intermediate vinylallenes underwent a variety of electrocyclization reactions which depended on the nature of the additional substituent at C-1. 10-Benzylideneanthrone and 4-benzylidene-1-tetralones, respectively, were obtained when this substituent was phenyl or vinyl. 1-(Alkynylphenyl)-2-benzylidenebenzocylobuten-1-ols were converted to mixtures of 4-benzylidene-1,4-naphthoquinonemethides, 2,3-dibenzylidene-1-indanones, and 10-phenylbenzofluorenone.
