52033-69-9Relevant academic research and scientific papers
Regioselective construction of indene skeletons by palladium-catalyzed annulation of alkynylborates with o-iodophenyl ketones
Shimamoto, Yasuhiro,Sunaba, Hanako,Ishida, Naoki,Murakami, Masahiro
, p. 1421 - 1424 (2013)
A palladium-catalyzed annulation reaction of alkynylborates with o-iodophenyl ketones to form indenes is described. Highly substituted indene skeletons are efficiently constructed with site-specific installation of the substituents. Alkynylborates react w
Selective Divergent Synthesis of Indanols, Indanones, and Indenes via Acid-Mediated Cyclization of (Z)- and (E)-(2-Stilbenyl)methanols and Its Application for the Synthesis of Paucifloral F Derivatives
Jongcharoenkamol, Jira,Chuathong, Patsapon,Amako, Yuka,Kono, Masato,Poonswat, Kasam,Ruchirawat, Somsak,Ploypradith, Poonsakdi
, p. 13184 - 13210 (2018/11/02)
Starting from bromo/iodobenzaldehyde derivatives, the corresponding (Z)- and (E)-(2-stilbenyl)methanols could be prepared in 2-5 steps via Pd-catalyzed cross-coupling reactions (Sonogashira and Heck reactions) followed by aryllithium/aryl Grignard addition. For the (E)-stilbenes, subsequent acid-mediated cyclization using p-TsOH immobilized on silica (PTS-Si) at low temperatures furnished the 2,3-trans-1-indanols with complete stereocontrol at the C2-C3. Further oxidization of the alcohol provided the indanones, which are structurally related to the natural product paucifloral F. At higher temperatures, 1,2- and 2,3-disubstituted indenes could be selectively prepared in good to excellent yields. On the other hand, the (Z)-stilbenes, under similar conditions (PTS-Si), did not give the indanols; only the 1,2-disubstituted indenes could be obtained. To gain further insights into the stereochemistry at C2-C3 for the (Z)-stilbenes, hydride or azide was employed as a nucleophile; the corresponding indane products were obtained with the cis stereochemistry at the C2-C3. Thus, the (Z)- or (E)-olefin geometry of the substrate directed the stereoselective indanyl cyclization to furnish the cis or trans at the C2-C3 ring junction, respectively, while reaction conditions controlled the selectivity of the product types.
Niobium-catalyzed activation of CF3 group on alkene: Synthesis of substituted indenes
Fuchibe, Kohei,Atobe, Kohei,Fujita, Yukari,Mori, Keiji,Akiyama, Takahiko
supporting information; experimental part, p. 867 - 869 (2011/01/07)
A CF3 group attached to an alkene functionality was activated by a zero-valent niobium catalyst to generate niobium alkenylcarbenoid species. The niobium carbenoid species then underwent insertion to an internal aromatic C-H σ bond to give inde
Sigmatropic Rearrangements of 1,1-Diarylindenes. Migratory Aptitudes of Aryl Migration in the Ground and Electronically Excited States
Manning, Carl,McClory, Michael R.,McCullough, John J.
, p. 919 - 930 (2007/10/02)
The photochemical and thermal rearrangements of 1,1-diarylindenes to give 2,3-diarylindenes have been investigated.Migratory aptitudes of p-X-phenyl vs. phenyl were determined for X =Br,CN, and OCH3 in the photochemical and thermal migrations.The identities of the products of these rearrangements were established by unambiguous synthesis, and the synthetic work is described.Product ratios were generally determined by NMR techniques, but VPC and isotope dilution were also used in the case of 1-(p-cyanophenyl)-1-phenylindene reactions.The excited-state reactions (direct and triplet sensitized) are highly selective, migration of the substituted phenyl group being favored for all three substituents.The thermal reactions, in contrast, are quite unselective, phenyl migrating almost as readily as the substituted phenyl group in all cases.Quantum yields for the rearrangement in the case of 1,1-diphenylindene and 1-(p-cyanophenyl)-1-phenylindene were 0.80 and 0.4, respectively (direct irradiation), and 0.43 and 0.53 (sensitized reactions).The results of the thermal reactions and results from the literature are discussed in terms of bond-dissociation energies and transition-state-delocalization energies calculated by using the Hueckel theory.Neither approach led to a satisfactory interpretation.The excited-state migrations are consistent with charge-transfer stabilization of the transition state, which can be estimated from oxidation and reduction potentials by using Weller's equation.
