16275-01-7Relevant academic research and scientific papers
An acid-catalyzed cyclialkylation that provides rapid access to a twisted molecular basket
Hermann, Keith,Turner, Daniel A.,Hadad, Christopher M.,Badjic, Jovica D.
, p. 8301 - 8305 (2012)
Twist of fate: Expanding the scope of cavity-containing compounds is essential for developing more efficient sensors and catalysts. This report describes an efficient cyclialkylation reaction that provides rapid access to a novel C3 symmetric a
Total synthesis of resveratrol-based natural products using a palladium-catalyzed decarboxylative arylation and an oxidative heck reaction
Klotter, Felix,Studer, Armido
supporting information, p. 2473 - 2476 (2014/03/21)
Controlled access to resveratrol-based natural products is offered by a novel, modular concept. A common building block readily available on a large scale serves as the starting material for the introduction of structurally important aryl groups by a Pd-c
Neutral dimethylzirconocene complexes as initiators for the ring-opening polymerization of ε-caprolactone
Villasenor, Elena,Gutierrez-Gonzalez, Ruben,Carrillo-Hermosilla, Fernando,Fernandez-Galan, Rafael,Lopez-Solera, Isabel,Fernandez-Pacheco, Ana Rodriguez,Antinolo, Antonio
, p. 1184 - 1196 (2013/04/10)
The synthesis, structures, and ring-opening polymerization (ROP) activity of new dimethyl-ansa- and -non-ansa-zirconocene complexes are reported. The substituted indene precursors 1-C9H7R [R = CH3 (1), CH2Ph (2) and C2H4(C4H 7O2) (3)] were synthesised by treating RBr [R = CH 2Ph and C2H4(C4H7O 2)] or MeI with indenyllithium. Likewise, bridged indenyl/cyclopentadiene compounds [Me2Si(3-C9H 6R)(C5Me4H)] [R = H (4), CH3 (5), CH2Ph (6) and C2H4(C4H 7O2) (7)] were obtained by treating the lithium salt of the appropriately substituted indene with ClSiMe2(C 5Me4H). ansa-Indenyl-cyclopentadienylmetallocenes [Zr{Me2Si(3-η5-C9H5R) (η5-C5Me4)}Cl2] [R = H (8), CH3 (9), CH2Ph (10), C2H4(C 4H7O2) (11)] were subsequently obtained by treating the dilithium salts of the corresponding ligands with ZrCl4 in toluene. The dimethyl derivatives [Zr{Me2Si(3-η5- C9H5R)(η5-C5Me 4)}Me2] [R = H (12), CH3 (13), CH2Ph (14), C2H4(C4H7O2) (15)] were prepared by treating the corresponding ansa-zirconocene dichloride complex with MgMeBr. Dialkyl derivative [Zr{Me2Si{3-η5-C 9H5(CH2Ph)}(η5-C 5Me4)}(CH2SiMe3)2] (16) was prepared by adding 2 equiv. of LiCH2SiMe3 to complex 10. Mixed indenyl/cyclopentadienylzirconocene complexes [Zr(η5- C9H6R)(η5-C5H 5)Cl2] [R = H (17), C2H4(C 4H7O2) (18)] were prepared by treating the lithium salt of the appropriately substituted indene with [Zr(η5- C5H5)Cl3]. Likewise, dimethyl derivatives [Zr(η5-C9H6R)(η5-C 5H5)Me2] [R = H (19), C2H 4(C4H7O2) (20)] were prepared by treating the corresponding mixed indenyl/cyclopentadienyl dichloride complex with 2 equiv. of MgMeBr. The X-ray crystal structures of 7, 12, and 13 were also established. Finally, comparative catalytic studies of zirconium complexes 12-16, 19 and 20 in ROP reactions of ε-caprolactone are described. Synthesis, characterization, and catalytic studies of new dimethyl-ansa- and -non-ansa-zirconocene complexes for ring-opening polymerization of ε-caprolactone are described. Copyright
Gold for the generation and control of fluxional barbaralyl cations
McGonigal, Paul R.,De Leon, Claudia,Wang, Yahui,Homs, Anna,Solorio-Alvarado, Cesar R.,Echavarren, Antonio M.
, p. 13093 - 13096 (2013/03/13)
Fluxional molecules which rapidly pass back and forth between a large number of constitutional isomers through low-energy rearrangements have fascinated chemists owing to their role in the study of fundamental theoretical concepts[ 2] and their potential to adapt their chemical structures in response to their environment or to act as prototypical molecular transport systems. They represent a facet of systems chemistry that is relatively unexplored, in which a dynamic structural library can be contained within a single molecule. The 9-barbaralyl cation (1) is a hugely fluxional C9H9 + hydrocarbon that exists as a mixture of 181 400 degenerate forms which interconvert rapidly at temperatures as low as -135 °C-each carbon atom may exchange with every other carbon atom in the structure through a series of pericyclic reactions. Unlike the neutral homologues semibullvalene (2; two degenerate tautomers) and bullvalene (3; 1209600 degenerate tautomers), which are stable compounds under ambient conditions, 1 is highly reactive and undergoes irreversible rearrangement to 1,4-bishomotropylium cation (4) above -125 °C. Functionalized barbaralanes may be suitable candidates for switchable, fluxional molecules. However, the difficulty in handling these compounds coupled with the low-yielding, multistep syntheses and harsh reaction conditions (typically featuring strongly or super acidic media) employed in the generation of 1 and its derivatives have so far limited the extent to which the chemistry of this fascinating dynamic carbon skeleton has been explored.
1,2,3-trisubstituted indanes by highly diastereoselective palladium-catalyzed oxyarylation of indenes with arylboronic acids and nitroxides
Kirchberg, Sylvia,Froehlich, Roland,Studer, Armido
supporting information; experimental part, p. 6877 - 6880 (2010/12/19)
Chemecal quation presented Excellent stereoselectivity is obtained in the synthesis of biologically interesting 1,2,3-trisubstituted indanes B by the reaction of readily prepared 3-substituted indenes A with commercially available arylboronic acids by using various TEMPO derivatives as external oxidants and Pd(OAc)2 as a catalyst. The anti,anti isomers are formed and reactions occur stereospecifically under mild conditions.
ω-Phenylalkyl substituted amido functionalized ansa half-sandwich complexes of titanium and zirconium and metallacycles thereof as catalyst precursors for homogeneous ethylene polymerization
Alt, Helmut G.,Reb, Alexander,Kundu, Kalipada
, p. 211 - 221 (2007/10/03)
The preparation and characterization of ω-phenylalkyl substituted ansa half-sandwich dichloride complexes of titanium and zirconium is described. These complexes react with butyllithium to give metallacycles via a CH activation reaction on the ortho posit
Zirconium bis-indenyl compounds. Synthesis and X-ray crystallography study of 1- and 2-substituted bis(R-indenyl)zirconium dichloride metallocenes
Grimmer, Neil E.,Coville, Neil J.,De Koning, Charles B.,Smith, Jeremy M.,Cook, Leanne M.
, p. 112 - 127 (2007/10/03)
A series of 1- and 2-substituted indenyl ligands were prepared and used in the synthesis of [1-R-Ind]2ZrCl2 [R = Me (2b), Et (4b), iPr (5b), tBu (6b), SiMe3 (8b), Ph (10b), Bz (12b), 1-Naph (14b)] and [2-R-Ind]2ZrCl2 [R = Me (1b), Et (3b), SiMe3 (7b), Ph (9b), Bz (11b), 1-Naph (13b)] metallocenes. An X-ray crystallographic study of 4b and 10b showed the complexes to be the racemic diastereomers (4b, both the R,R and S,S-enantiomers and 10b, the S,S-enantiomer). The X-ray data together with NMR spectral data revealed that the size of the substituent influenced the orientation the two indenyl ligands of the metallocenes. The 4b diastereomers are both found to crystallize with their ethyl groups syn (bis-central) with respect to each other whereas the larger phenyl groups in 10b results in an anti (bis-lateral) orientation of the indenyl ligands.
ω-phenylalkyl-substituted zirconocene dichloride complexes as catalyst precursors for homogeneous ethylene polymerization
Licht, Erik H.,Alt, Helmut G.,Karim, M. Manzurul
, p. 275 - 287 (2007/10/03)
The reaction of ω-phenyl-1-bromoalkanes with cyclopentadienyl sodium, indenyl lithium or fluorenyl lithium forms ω-phenylalkyl-substituted ligand precursors in high yields. The corresponding anions react with zirconium tetrachloride to give ω-phenylalkyl-
Verbrueckte Indenyliden-Cyclopentadienylidenkomplexe des Typs (C9H5CH2Ph-X-C5H4)MCl2 (X=CMe2, SiMe2; M=Zr, Hf) als Metallocenkatalysatoren fuer die Ethylenpolymerisati
Alt, Helmut G.,Jung, Michael,Milius, Wolfgang
, p. 111 - 121 (2007/10/03)
The synthesis and NMR spectroscopic characterization of new ansa metallocene dichloride complexes of the type (C9H5CH2Ph-X-C5H4)ZrCl2 (X=CMe2, SiMe2; M=Zr, Hf) are rep
Photochemistry of 2-Vinylstilbene, 1,2-Distyrylbenzene, and 2,2'-Distyrylbiphenyl Absorbed on Silica Gel. Influence of Ground-State Conformers on Formation of Photoproducts
Tol, Arie J. W.,Laarhoven, Wim H.
, p. 1663 - 1668 (2007/10/02)
Irradiation of 2-vinylstilbene (1) absorbed on silica gel gives rise to several products.In addition to exo- and endo-5-phenylbenzobicyclohex-2-enes (2 and 3) (the sole products formed in solution) derivatives of naphthalene and of indene are forme
