196215

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Transamidation of primary amides with amines catalyzed by zirconocene dichloride.

Benjamin N Atkinson et al.

Chemical communications (Cambridge, England), 48(95), 11626-11628 (2012-10-26)

Zirconocene dichloride (Cp(2)ZrCl(2)) has been shown to be an effective catalyst for the transamidation of primary amides with amines in cyclohexane at 80 °C in 5-24 hours. For favourable substrates, the reaction can be performed at temperatures as low as

Structure of zirconocene complexes relevant for olefin catalysis: infrared fingerprint of the Zr(C(5)H(5))(2)(OH)(CH(3)CN)(+) cation in the gas phase.

Anita Lagutschenkov et al.

The journal of physical chemistry. A, 114(5), 2073-2079 (2010-01-21)

Cationic zirconocene complexes are active species in Ziegler-Natta catalysis for olefin polymerization. Their structure and metal-ligand bond strength strongly influence their activity. In the present work, the infrared multiphoton dissociation (IRMPD) spectrum of mass selected Zr(C(5)H(5))(2)(OH)(CH(3)CN)(+) cations was obtained in

Zirconocene dichloride catalysed one-pot synthesis of pyrroles through nitroalkene-enamine assembly

Goyal S, et al.

Royal Society of Chemistry Advances, 5, 3187-3195 (2015)

Aldrichimica Acta, 17, 28-28 (1984)

Enantioselective route from carbohydrates to cyclooctane polyols.

Leo A Paquette et al.

Organic letters, 7(3), 511-513 (2005-01-28)

[reaction: see text] A synthetic route to select cyclooctane-1,2,3-triols and 1,2,3,4,5-pentaols has been defined. The starting materials are d-glucose or d-arabinose, and the key steps consist of a zirconocene-promoted ring contraction, a [3,3] sigmatropic rearrangement, and more extended functionalization of

Formal total synthesis of (+/-)-estrone and zirconocene-promoted cyclization of 2-fluoro-1,7-octadienes and ru-catalyzed ring closing metathesis.

Pavel Herrmann et al.

The Journal of organic chemistry, 73(16), 6202-6206 (2008-07-18)

A new and diastereoselective method for the synthesis of the estrone skeleton from a substituted styrene based on sequential 3-fold use of Cp 2ZrBu 2 (oxidative addition-alkylation and two cyclization-alkylation sequences) and a ruthenium complex catalyzed RC-metathesis of a sterically

Unusual temperature effects in propene polymerization using stereorigid zirconocene catalysts.

Vidar R Jensen et al.

Chemphyschem : a European journal of chemical physics and physical chemistry, 6(9), 1929-1933 (2005-08-03)

Free Car-Parrinello molecular dynamics (CPMD) simulations of four diastereomers of the zirconium-propene complexes [{iPr(3-iPr-CpFlu)}ZriBu(C3H6)]+ (Cp=cyclopentadienyl; Flu=fluorenyl) provide valuable insight into the mechanism and stereocontrol of propene polymerization with stereorigid metallocenes. Spontaneous insertion of propene into the zirconium-isobutyl bond is not

One-pot multicomponent synthesis of azaindoles and pyrroles from one molecule of a silicon-tethered diyne and three or two molecules of organonitriles mediated by zirconocene.

Shaoguang Zhang et al.

Chemistry (Weinheim an der Bergstrasse, Germany), 15(46), 12608-12617 (2009-11-03)

A zirconocene-mediated one-pot multicomponent synthesis process leading to the synthesis of pyrrolo[3,2-c]pyridine (5-azaindoles) and pyrrole derivatives has been developed starting from a silicon-tethered diyne and three or two different or identical organonitriles. Pyrrolo[3,2-c]pyridine and pyrrole derivatives with diverse structures and

Developments of chiral metallocenes as polymerization catalysts.

Yuushou Nakayama et al.

Molecules (Basel, Switzerland), 10(6), 620-633 (2007-11-17)

This review article describes developments in chiral metallocenes as polymerization catalysts focusing on C2 symmetric ansa-zirconocene complexes. Selective synthesis of rac-isomers of ansa-zirconocenes are surveyed. Isospecific polymerizations of propylene catalyzed by chiral zirconocenes are summarized. Advanced series of polymerizations by

Functionalised cyclopentadienyl zirconium compounds as potential anticancer drugs.

Olivia R Allen et al.

Dalton transactions (Cambridge, England : 2003), (39)(39), 5293-5295 (2008-10-02)

New neutral and ionic functionalised zirconocene dichloride compounds have been isolated and characterised. The ionic zirconocene exhibits excellent cytotoxicity against a range of human tumour cell lines, which represents the first active anticancer zirconocene dichloride compound.

Generation of ultra-high-molecular-weight polyethylene from metallocenes immobilized onto N-doped graphene nanoplatelets.

Baekhap Choi et al.

Macromolecular rapid communications, 34(6), 533-538 (2013-01-29)

Catalytic natures of organometallic catalysts are modulated by coordinating organic ligands with proper steric and electronic properties to metal centers. Carbon-based nanomaterials such as graphene nanoplatelets are used with and without N-doping and multiwalled carbon nanotube as a ligand for

Carbon monoxide-induced dinitrogen cleavage with group 4 metallocenes: reaction scope and coupling to N-H bond formation and CO deoxygenation.

Donald J Knobloch et al.

Journal of the American Chemical Society, 132(30), 10553-10564 (2010-07-29)

The scope of CO-induced N(2) cleavage in a series of zirconocene and hafnocene complexes containing activated, side-on bound dinitrogen ligands has been studied. In each case, bridging oxamidide ligands, [N(2)C(2)O(2)](4-), were formed from N-N bond cleavage coupled to N-C and

Medium-sized carbocycles by a zirconocene-catalyzed tandem formal ring expansion-magnesation reaction of alkenyl-substituted cyclic enol ethers.

José Barluenga et al.

Organic letters, 9(16), 3081-3084 (2007-07-20)

A new regio- and stereoselective zirconocene-catalyzed reaction for the synthesis of medium-sized rings is described. The global reaction supposes a formal ring expansion of a cyclic enol ether to give a functionalized carbocycle.

Intramolecular hydroamination/cyclisation of aminoallenes mediated by a cationic zirconocene catalyst: a computational mechanistic study.

Sven Tobisch

Dalton transactions (Cambridge, England : 2003), (35)(35), 4277-4285 (2006-08-26)

The complete sequence of steps of a tentative catalytic cycle for intramolecular hydroamination/cyclisation (IHC) of 4,5-hexadien-1-ylamine (1) by a prototypical cationic [Cp(2)ZrCH(3)](+) zirconocene precatalyst (2) has been examined by employing a gradient-corrected DFT method. The predicted smooth overall reaction energy

Frustrated Lewis pairs beyond the main group: synthesis, reactivity, and small molecule activation with cationic zirconocene-phosphinoaryloxide complexes.

Andy M Chapman et al.

Journal of the American Chemical Society, 133(45), 18463-18478 (2011-10-01)

The extension of the frustrated Lewis pair (FLP) concept to the transition series with cationic zirconocene-phosphinoaryloxide complexes is demonstrated. Such complexes mimic the reactivity of main group FLPs in reactions such as heterolytic hydrogen cleavage, CO(2) activation, olefin and alkyne

Zirconocene and Si-tethered diynes: a happy match directed toward organometallic chemistry and organic synthesis.

Wen-Xiong Zhang et al.

Accounts of chemical research, 44(7), 541-551 (2011-05-27)

Characterizing reactive organometallic intermediates is critical for understanding the mechanistic aspects of metal-mediated organic reactions. Moreover, the isolation of reactive organometallic intermediates can often result in the ability to design new synthetic methods. In this Account, we outline synthetic methods

Zirconocene-mediated highly regio- and stereoselective synthesis of multisubstituted olefins starting from 1-alkynylboronates.

Yasushi Nishihara et al.

Journal of the American Chemical Society, 129(42), 12634-12635 (2007-10-04)

A selective synthesis of hydroxyborate anions as novel anchors for zirconocene catalysts.

Christine Bibal et al.

Dalton transactions (Cambridge, England : 2003), (21)(21), 2866-2870 (2008-05-15)

A new family of hydroxytris(pentafluorophenyl)borate anions [B(C6F5)3OH](-) associated with organic and aprotic cations c+ (imidazolium, pyrrolidinium and phosphonium) has been prepared by a general one-pot synthesis that implies the chloride borate analogues [B(C6F5)3Cl](-)[c]+. The [c]+[B(C6F5)3OH](-) salts have been isolated and

Hydroamination/cyclization of aminoalkenes using cationic zirconocene and titanocene catalysts.

Denis V Gribkov et al.

Angewandte Chemie (International ed. in English), 43(41), 5542-5546 (2004-10-16)

In pursuit of pestalotiopsin a via zirconocene-mediated ring contraction.

Shuzhi Dong et al.

Organic letters, 8(11), 2429-2431 (2006-05-19)

[reaction: see text] An asymmetric route from the epimeric beta-hydroxy esters 4 and 5 to the densely functionalized (+)-10 and (-)-10, respectively, is described. Either cyclobutanol can be made available as the predominant product. The levorotatory antipode has been transformed

Mild and selective hydrozirconation of amides to aldehydes using Cp2Zr(H)Cl: scope and mechanistic insight.

Jared T Spletstoser et al.

Journal of the American Chemical Society, 129(11), 3408-3419 (2007-02-24)

An investigation of the use of Cp2Zr(H)Cl (Schwartz's reagent) to reduce a variety of amides to the corresponding aldehydes under very mild reaction conditions and in high yields is reported. A range of tertiary amides, including Weinreb's amides, can be

Tandem insertion of halocarbenoids and lithium acetylides into zirconacycles: a novel rearrangement to zirconium alkenylidenates by β-addition to an alkynyl zirconocene.

Jozef Stec et al.

Chemistry (Weinheim an der Bergstrasse, Germany), 17(17), 4896-4904 (2011-03-23)

Tandem insertion of 1,1-dihalo-1-lithio species (halocarbenoids) and lithium alkynides into zirconacyclopentenes and zirconcyclopentanes affords carbocyclic products in high yields via an unusual rearrangement that probably involves addition of an organolithium species to the β-position of a zirconium-alkyne complex to give

Zirconocene-mediated synthesis of cyclobutabenzenes.

José Barluenga et al.

Organic letters, 10(20), 4469-4471 (2008-09-20)

A new, mild, one-pot method for the synthesis of cyclobutabenzenes by the zirconium-promoted cross-coupling reaction of aryllithium compounds and alkenyl bromides is reported. Formation of an arynezirconocene complex and its regioselective coupling with an alkenyl bromide are the key steps

Silver(I)-catalyzed addition of zirconocenes to glycal epoxides. A new synthesis of alpha-C-glycosides.

Peter Wipf et al.

Organic letters, 7(3), 483-485 (2005-01-28)

[reaction: see text] Hydrozirconation of terminal alkynes, followed by AgClO4-catalyzed in situ addition of the resultant alkenylzirconocenes to 1,2-anhydrosugars (glycal epoxides) leads to alpha-C-glycosides in moderate to high yields.

Double carbonylation of zirconocene-alkyne complexes.

Shizue Mito et al.

Chemical communications (Cambridge, England), (19)(19), 2495-2496 (2005-05-12)

Zirconocene-alkyne complexes prepared from Cp2ZrBu2, phosphines and alkynes reacted with CO to give double carbonylation products, 4-hydroxycyclobuten-1-one derivatives after hydrolysis.

Carboxylation of an ansa-zirconocene dinitrogen complex: regiospecific hydrazine synthesis from N2 and CO2.

Donald J Knobloch et al.

Journal of the American Chemical Society, 130(13), 4248-4249 (2008-03-11)

Addition of 2 equiv of carbon dioxide to the ansa-zirconocene dinitrogen complex resulted in selective insertion into each zirconium nitrogen bond, forming a C2 symmetric dicarboxylated diazenido compound. Treatment with excess Me3SiI furnished the ansa-zirconocene diiodide along with the N,N'-dicarboxylated

Reactive intermediates formed during olefin polymerization by methylalumoxane-activated ansa-zirconocene catalysts: identification of a chain-carrying intermediate by NMR methods.

Dmitrii E Babushkin et al.

Journal of the American Chemical Society, 132(2), 452-453 (2009-12-22)

Addition of 1-hexene to methylalumoxane-activated catalyst systems based on rac-Me(2)Si(ind)(2)ZrMe(2) causes, concurrent with polyhexene formation and diminution of the otherwise prevalent cation [rac-Me(2)Si(ind)(2)Zr(mu-Me)(2)AlMe(2)](+), formation of a hitherto unobserved species [rac-Me(2)Si(ind)(2)Zr(mu-R)(mu-Me)AlMe(2)](+), where R is a Zr-bound polyhexyl chain. As hexene is

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