Cyclopentadienyltitanium Trichloride

Gorsich, Richard D.

doi:10.1021/ja01550a084

Cited by 65 publications

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“…[38] Deuterated solvents were firstly degassed by several freeze-thaw cycles, held at room temperature over fresh activated 4 Å molecular sieves (10 % w/v) for several days, and then stored at room temperature over freshly activated 4 Å molecular sieves (10 % w/v). Compounds TiCpCl 3 [39,40] and Ti(η 5 -C 5 H 4 SiMe 2 Cl)Cl 3 [41] were prepared by a known procedure. Aniline, p-toluidine, cyclohexylamine, 2,6-dimethylaniline, 3,5-di-tert-butyl-2-hydroxybenzaldehyde, salicylaldehyde, paraformaldehyde, 2,4-ditert-butylphenol, LiBH 4 , NaBH 4 and AlLiH 4 , LiMe (1.6  solution in Et 2 O) or MgClMe (3  solution in thf), MgClEt (2  solution in Et 2 O) and LiPh [2  solution in cyclohexane/ethyl ether mixture (Aldrich)] were used as received.…”

Section: Methodsmentioning

confidence: 99%

Monocyclopentadienyl Phenoxido–Amino and Phenoxido–Amido Titanium Complexes: Synthesis, Characterisation, and Reactivity of Asymmetric Metal Centre Derivatives

et al. 2008

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Reduction of phenol-imine derivatives RЈN=CH(3,5-R 2 C 6 H 2 -2-OH) (R = tBu; RЈ = C 6 H 5 1a, p-MeC 6 H 4 1b, Cy 1c, tBu 1d, 2,6-Me 2 C 6 H 3 1e; R = H; RЈ = p-MeC 6 H 4 1f; Cy = cyclohexyl) with MBH 4 (M = Li, Na) or AlLiH 4 in ethyl ether or thf at room temperature affords the phenol-amine compounds RЈNHCH 2 (3,5-R 2 C 6 H 2 -2-OH) 2a-c and 2e,f. The N-R- [2,4-ditert-butyl]benzo-1-oxa-3-azine species (R = tBu 2d1, 2,6-Me 2 C 6 H 3 2e1) are obtained by Mannich reaction of 2,4-ditert-butylphenol with RNH 2 in refluxing methanol. Intermediate 2d1 is converted in ethanol at room temperature into N-tert-butyl [2-hydroxy-3,5-di-tert-butyl]benzylamine (2d), whereas 2e is not obtained from 2e1 by using this procedure. N-alkyl,N-tert-butyl[2-hydroxy-3,5-di-tert-butyl]benzylamine compounds tBuN(R)CH

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Section: Methodsmentioning

confidence: 99%

Monocyclopentadienyl Phenoxido–Amino and Phenoxido–Amido Titanium Complexes: Synthesis, Characterisation, and Reactivity of Asymmetric Metal Centre Derivatives

et al. 2008

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“…NEt 3 (Aldrich) was distilled before use and stored over 4 Å molecular sieves. [Ti(η 5 -C 5 H 5 )Cl 3 ], [28] [Ti(η 5 -C 5 Me 5 )Cl 3 ], [29] [Ti(η 5 -C 5 H 4 SiMe 3 )Cl 3 ], [30] [Zr(η 5 -C 5 H 5 )Cl 3 ]·DME [31] and [Zr(η 5 -C 5 Me 5 )Cl 3 ] [32] were prepared by known procedures. Polymerization-grade ethylene was used as received.…”

Section: Methodsmentioning

confidence: 99%

Preparation of Diamidochloro(cyclopentadienyl)titanium Derivatives as Pre‐Catalysts for Olefin Polymerization − X‐ray Molecular Structure of [Ti(η⁵‐C₅H₅){1,2‐C₆H₄(NCH₂CH₂CH₃)₂}Cl] and [Ti{η⁵‐C₅H₄(SiMe₃)}{1,2‐C₆H₄(NCH₂CH₂CH₃)₂}Cl]

2004

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Keywords: Cyclopentadienyl ligands / N ligands / Olefin polymerization / TitaniumThe synthesis of N,NЈ-alkyl 1,2-phenylenediamines 1,2-C 6 H 4 (NHR) 2 [R = CH 2 CH 2 CH 3 (nPr), CH 2 tBu (Np)] was carried out in three steps by lithiation of the primary 1,2-phenylenediamine, reaction with the appropriate acyl chloride and reduction with LiAlH 4 . The addition of nBuLi to a stirred solution of N,NЈ-alkyl diamines in cold hexane resulted in the immediate deposition of the corresponding lithium salts, which react with [MCp

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“…[la]. To a soln./suspension of trichlorojcyclopentadieny1)titanium (2) [28] (1 1 .O g, 50 mmol, freshly sublimed) in 400 ml of dry Et,O 1,21S,6-di-O-isopropy/idene-~-D-glucofuranose (3, 26.0 g, 100 mmol; crystallised from cyclohexane) was added (Ar, exclusion of moisture). After stirring for 2 min at r.t., a soln.…”

Section: Experimental Partmentioning

confidence: 99%

“…To a soln./suspension of 2 [28] (1 I .0 g, 50.1 mmol; freshly sublimed) in 400 ml ofdry Et20, i-PrOH (6.0 g, 100 mmol; dried over4-A molecular sieves) and, after 5 min, Et,N (15.2 ml, 110 mmol) in 125 ml of Et20 were added dropwise within 1 h (Ar). After stirring over night at r.t., Et,N .HCI (13.5 g after drying) was removed by filtralion under Ar and washed with Et20 (3 x 50 ml).…”

Section: Chloro(cyclopentadnyl)bis(i2:5~-di-0-isopropylidene-a-o-glmentioning

confidence: 99%

Enantio‐ and Diastereoselective Aldol‐Reaction of 2,6‐Dimethylphenyl Propionate Using Titanium‐Carbohydrate Complexes

Duthaler

Herold

Wyler‐Helfer

et al. 1990

Helvetica Chimica Acta

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Chloro(cyclopentadienyl)bis( 1,2 : 5.6-di-0 -isopropylidene-cc -~-glucofuranos-3-0 -yl)titanium (1) is used for the transmetallation of Li-enolates obtained from propionyl derivatives. While such Ti-enolates of ketones and hydrazones appear to be unreactive, the (E)-enolate 13 of 2.6-dimethylphenyl propionate (1 1) adds to the re-side of aldehydes, affording various s-vn-aldols 14 with high dia-and enantioselectivity (92-97% ds, 91-97% ee, cJ Scheme 2 and Table 1). Racemic syn-aldols (f)-14 are obtained analogously from the achiral bis(2-propyloxy)-Tienolate 15 (Scheme 2 and Table 2). In contrast to the unstable Li-enolatc 10, the Ti-enolates 13 and 15 isomerize at -30", presumably to the thermodynamically more stable (L)-enolates (Scheme 4 ) . While the diastereoselectivity of the achirdl enolate 15 is lost upon this equilibration, the chiral (Z)-enolate 27 quite unexpectedly affords unti-aldols 12 of high optical purity (94~-98 % ee) and, in most cases, with acceptable-to-good diastereoselectivity (82-90% ds). Notable exceptions are branched unsaturated and aromatic aldehydes which form a greater proportion of sy-epimers of moderate optical purity (Scheme 5 and Table 3). Consistent with these findings, re-facialand anti-selective aldol-addition is also exhibited by the (Z)-configurated Ti-enolate 22 of N-propionyl-oxazolidinone 19 (Scheme 3). 1.Introduction. -In previous communications [l], we have described the synthesis of chloro(cyclopentadienyl)bis( 1,2 : 5,6-di-0 -isopropylidene-a -~-glucofuranos-3-0 -yl)-titanate (1) from [TiCpCl,] (2) and diacetoneglucose (DAGOH) 3. The novel complex 1, whose structure was studied by X-ray diffraction analysis, 'H-, and "C-NMR [ld], proved to be a potent chiral template for enantioselective reactions. Exchange of the C1-atom in 1 for ally1 (+ 4) or ester-enolates (+ 5 or 6) and reaction with aldehydes gives homoallyl alcohols 7 [la], /I-hydroxy-esters 8 [ 1 b], and threo-& hydroxy-a -amino acids 9 [lc], respectively, with high enantio-and diastereoselectivity (Scheme I ) . This accomplishment led to the experiments with propionyl-enolates described below.The stereocontrolled aldol addition of propionyl-enolates is one of the most important reactions for the construction of complex acyclic or macrocyclic natural products of propionate/acetate biogenesis 121. While excellent methods are known for the enantioselective synthesis of syn -aldols (cf.

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Cyclopentadienyltitanium Trichloride

Cited by 65 publications

References 0 publications

Monocyclopentadienyl Phenoxido–Amino and Phenoxido–Amido Titanium Complexes: Synthesis, Characterisation, and Reactivity of Asymmetric Metal Centre Derivatives

Monocyclopentadienyl Phenoxido–Amino and Phenoxido–Amido Titanium Complexes: Synthesis, Characterisation, and Reactivity of Asymmetric Metal Centre Derivatives

Preparation of Diamidochloro(cyclopentadienyl)titanium Derivatives as Pre‐Catalysts for Olefin Polymerization − X‐ray Molecular Structure of [Ti(η⁵‐C₅H₅){1,2‐C₆H₄(NCH₂CH₂CH₃)₂}Cl] and [Ti{η⁵‐C₅H₄(SiMe₃)}{1,2‐C₆H₄(NCH₂CH₂CH₃)₂}Cl]

Enantio‐ and Diastereoselective Aldol‐Reaction of 2,6‐Dimethylphenyl Propionate Using Titanium‐Carbohydrate Complexes

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Cyclopentadienyltitanium Trichloride

Cited by 65 publications

References 0 publications

Monocyclopentadienyl Phenoxido–Amino and Phenoxido–Amido Titanium Complexes: Synthesis, Characterisation, and Reactivity of Asymmetric Metal Centre Derivatives

Monocyclopentadienyl Phenoxido–Amino and Phenoxido–Amido Titanium Complexes: Synthesis, Characterisation, and Reactivity of Asymmetric Metal Centre Derivatives

Preparation of Diamidochloro(cyclopentadienyl)titanium Derivatives as Pre‐Catalysts for Olefin Polymerization − X‐ray Molecular Structure of [Ti(η5‐C5H5){1,2‐C6H4(NCH2CH2CH3)2}Cl] and [Ti{η5‐C5H4(SiMe3)}{1,2‐C6H4(NCH2CH2CH3)2}Cl]

Enantio‐ and Diastereoselective Aldol‐Reaction of 2,6‐Dimethylphenyl Propionate Using Titanium‐Carbohydrate Complexes

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Preparation of Diamidochloro(cyclopentadienyl)titanium Derivatives as Pre‐Catalysts for Olefin Polymerization − X‐ray Molecular Structure of [Ti(η⁵‐C₅H₅){1,2‐C₆H₄(NCH₂CH₂CH₃)₂}Cl] and [Ti{η⁵‐C₅H₄(SiMe₃)}{1,2‐C₆H₄(NCH₂CH₂CH₃)₂}Cl]