Titanium n Complexes

Bis(cyclopentadienyl)titanium(n) Complexes with Other Unsaturated Hydrocarbons 261... 

The reduction of Cp2TiCl2 with Mg in the presence of P(OEt)3 affords the titanium(n) complex Cp2Ti[P(OEt)3]2 which was used as a catalyst for the carbonyl olefination of thioacetals through a titanium-alkylidene intermediate (see Section 4.05.4.2.4 alkylidene complexes).1148... 

A range of chloride metathesis reactions of the monomeric titanium N,N -bis(trimethylsilyl)benzamidinato-imido complexes have been described. These... 

A dimethyltitanium complex bearing phosphinimide Hgands TiMe2[N=P(t-Bu)3]2 reacts with Ss to give the titanium pentasulfido complex TiS5[N=P(t-Bu)3]2 (Scheme 17) [58]. This result is in a sharp contrast to the... 

It has been reported that the zinc hexasulfido complex, Zn(S6)(TMEDA) (TMEDA=] r,] T,N, N -tetramethylethylenediamine) acts as a sulfur transfer reagent in an analogous manner as the above-mentioned titanium polysulfido complexes. The sulfur transfer reaction between Zn(S6)(TMEDA) and TiCp2Cl2 cleanly proceeds at room temperature to afford ZnCl2(TMEDA) and TiCp2S5 together with Ss (Scheme 51) [132]. This result suggests that... 

The anionic polymerization of isocyanates using NaCN as an initiator was first reported in I960.998 The living coordinative polymerization of n-hexylisocyanate has been described using the titanium(IV) complexes (345) (348).999-1001 A trifunctional initiator has also been used to prepare star polyisocyanates.1002... 

The first isolable alkenetitanium complex, the bis(pentamethylcyclopentadienyl)-titanium—ethylene complex 5, was prepared by Bercaw et al. by reduction of bis(penta-methylcyclopentadienyl)titanium dichloride in toluene with sodium amalgam under an atmosphere of ethylene (ca. 700 Torr) or from ( (n-C5Mc5)2Ti 2(fJ-N2)2 by treatment with ethylene [42], X-ray crystal structure analyses of 5 and of the ethylenebis(aryloxy)trimethyl-phosphanyltitanium complex 6 [53] revealed that the coordination of ethylene causes a substantial increase in the carbon—carbon double bond length from 1.337(2) A in free ethylene to 1.438(5) A and 1.425(3) A, respectively. Considerable bending of the hydrogen atoms out of the plane of the ethylene molecule is also observed. By comparison with structural data for other ethylene complexes and three-membered heterocyclic compounds, the structures of 5 and 6 would appear to be intermediate along the continuum between a Ti(11)-ethylene (4A) and a Ti(IV)-metallacyclopropane (4B) (Scheme 11.1) as... 

Table 11.11. 2-Alkenyl-l-(N,N-dibenzylamino)cyclopropanes formed from N,N-dibenzylformamide (48) and titanium-diene complexes generated in situ by ligand exchange.

Regioisomers of pyrrolizines 255 and their dihydroanlogues 256 were obtained as a mixture, in moderate yield, by reacting the 1,4,7-triketones 254 with titanium-nitrogen complexes (ClTi=NTMS, Cl2TiN(TMS)2, and N(TMS)3) prepared by reduction of TiCU with lithium under a nitrogen atmosphere (Scheme 69) <2004BCJ1655>. 

Unsymmetrical vicinal diols can be prepared from a three-component reaction of aldehydes, CO, and aminotroponiminate-ligated titanium dialkyl complexes. Solutions of Me2TiL,2 (L = N -dimethylaminolroponiminalc) react rapidly with CO at room temperature. Double methyl migration to CO produces an 2-acclonc complex which inserts the aldehyde to afford a titana-dioxolane and releases the unsymmetrical diol upon hydrolysis [65]. 

Titanium(iv) Complexes.—N-Donor Ligands. The oxidation of TiCl3 by the chlorinated alkyl cyanides CH2ClCN,CHCl2CN, CCI3CN, and CH2CICCI2CN... 

M. Hayashi, Y. Miyamoto, T. Inoue, and N. Oguni, Enantioselective trimethylsilylcyanation of some aldehydes catalyzed by chiral Schiff base-titanium alkoxide complexes, J. Org. Chem. 58 1515 (1993). 

Comparison of the titanium-pseudohalide complexes (86) and (88) shows nicely the different bonding of the pseudohalide, i.e. bent Ti—N—N vs. linear Ti—N—C of the N-bonded isocyanate and isothiocyanate. Table 9a shows that in isostructural M(tj5-Cp)2(NCO>2 (M = Ti, Zr)222 the N—C (b) bonds tend to be shorter than the C—O (c) bonds. This may point to a larger contribution of canonical structure (89) which has some C—O triple bond character in the bonding. 

Cross-coupling reactions 5-alkenylboron boron compounds, 9, 208 with alkenylpalladium(II) complexes, 8, 280 5-alkylboron boron, 9, 206 in alkyne C-H activations, 10, 157 5-alkynylboron compounds, 9, 212 5-allylboron compounds, 9, 212 allystannanes, 3, 840 for aryl and alkenyl ethers via copper catalysts, 10, 650 via palladium catalysts, 10, 654 5-arylboron boron compounds, 9, 208 with bis(alkoxide)titanium alkyne complexes, 4, 276 carbonyls and imines, 11, 66 in catalytic C-F activation, 1, 737, 1, 748 for C-C bond formation Cadiot-Chodkiewicz reaction, 11, 19 Hiyama reaction, 11, 23 Kumada-Tamao-Corriu reaction, 11, 20 via Migita-Kosugi-Stille reaction, 11, 12 Negishi coupling, 11, 27 overview, 11, 1-37 via Suzuki-Miyaura reaction, 11, 2 terminal alkyne reactions, 11, 15 for C-H activation, 10, 116-117 for C-N bonds via amination, 10, 706 diborons, 9, 167... 

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