Chlorotitanium Triisopropoxide

Petasis, Nicos A.

doi:10.1002/047084289x.rc152

Cited by 3 publications

(3 citation statements)

References 37 publications

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“…B(C 6 F 5 ) 3 (Aldrich) was dried with Me 3 SiCl and sublimed prior to use. 5 ,43b 8 , [Rh(1,5-cod)(μ-Cl)] 2 , [Ir(1,5-cod)(μ-Cl)] 2 , Cp 2 TiMe 2 , [Cp*Rh(μ-Cl)Cl] 2 , trans -RuMe 2 (PMe 3 ) 4 , and [Rh(1,5-cod)(dmpe)]PF 6 were synthesized by literature procedures.…”

Section: Methodsmentioning

confidence: 99%

Transition Metal-Catalyzed Formation of Boron−Nitrogen Bonds: Catalytic Dehydrocoupling of Amine-Borane Adducts to Form Aminoboranes and Borazines

et al. 2003

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A mild, catalytic dehydrocoupling route to aminoboranes and borazine derivatives from either primary or secondary amine-borane adducts has been developed using late transition metal complexes as precatalysts. The adduct Me(2)NH.BH(3) thermally eliminates hydrogen at 130 degrees C in the condensed phase to afford [Me(2)N-BH(2)](2) (1). Evidence for an intermolecular process, rather than an intramolecular reaction to form Me(2)N=BH(2) as an intermediate, was forthcoming from "hot tube" experiments where no appreciable dehydrocoupling of gaseous Me(2)NH.BH(3) was detected in the range 150-450 degrees C. The dehydrocoupling of Me(2)NH.BH(3) was found to be catalyzed by 0.5 mol % [Rh(1,5-cod)(mu-Cl)](2) in solution at 25 degrees C to give 1 quantitatively after ca. 8 h. The rate of dehydrocoupling was significantly enhanced if the temperature was raised or if the catalyst loading was increased. The catalytic activity of various other transition metal complexes (Ir, Ru, Pd) for the dehydrocoupling of Me(2)NH.BH(3) was also demonstrated. This new catalytic method was extended to other secondary adducts RR'NH.BH(3) which afforded the dimeric species [(1,4-C(4)H(8))N-BH(2)](2) (2) and [PhCH(2)(Me)N-BH(2)](2) (3) or the monomeric aminoborane (i)Pr(2)N=BH(2) (4) under mild conditions. A new synthetic approach to the linear compounds R(2)NH-BH(2)-NR(2)-BH(3) (5: R = Me; 6: R = 1,4-C(4)H(8)) was developed and subsequent catalytic dehydrocoupling of these species yielded the cyclics 1 and 2. The species 5 and 6 are postulated to be intermediates in the formation of 1 and 2 directly from the catalytic dehydrocoupling of the adducts R(2)NH.BH(3). The catalytic dehydrocoupling of NH(3).BH(3), MeNH(2).BH(3), and PhNH(2).BH(3) at 45 degrees C to give the borazine derivatives [RN-BH](3) (10: R = H; 11: R = Me; 12: R = Ph) was demonstrated. TEM analysis of the contents of the reaction solution for the [Rh(1,5-cod)(mu-Cl)](2) catalyzed dehydrocoupling of Me(2)NH.BH(3) together with Hg poisoning experiments suggested a heterogeneous catalytic process involving Rh(0) colloids.

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Section: Methodsmentioning

confidence: 99%

Transition Metal-Catalyzed Formation of Boron−Nitrogen Bonds: Catalytic Dehydrocoupling of Amine-Borane Adducts to Form Aminoboranes and Borazines

et al. 2003

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“…Ph 2 PH, PhPH 2 , [Rh(1,5-cod) 2 ][OTf] (1,5-cod = 1,5-cyclooctadiene), [Rh(1,5-cod)(dmpe)][PF 6 ] (dmpe = 1,2-bis(dimethylphosphino)ethane), [Rh(CO)(PPh 3 ) 3 H], [Ir(1,5-cod) 2 ][BF 4 ], Ru 3 (CO) 12 , [Pd(PPh 3 ) 4 ], PdCl 2 , PtCl 2 (Strem Chemicals), RhCl 3 , RhCl 3 hydrate (Pressure Chemical Co.), and [Rh(PPh 3 ) 3 Cl], Me 2 S·BH 3 (Aldrich) were purchased and used as received. i BuPH 2 was obtained from Cytec Canada Inc. PhPH 2 ·BH 3 , [{Rh(μ-Cl)(1,5-cod)} 2 ], [{Cp*Rh(μ-Cl)Cl} 2 ], [{Ir(μ-Cl)(coe) 2 } 2 ] (coe = cyclooctene), Cp 2 TiMe 2 , and [Pt(1,5-cod) 2 ] were prepared following literature procedures. Ph 2 PH·BH 3 was prepared using a procedure analogous to that used for PhPH 2 ·BH 3 …”

Section: Methodsmentioning

confidence: 99%

Transition Metal-Catalyzed Formation of Phosphorus−Boron Bonds: A New Route to Phosphinoborane Rings, Chains, and Macromolecules

et al. 2000

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A novel catalytic dehydrocoupling route for the synthesis of linear, cyclic, and polymeric phosphinoboranes has been developed. The dehydrocoupling of neat Ph 2 PH‚BH 3 , which is otherwise very slow below 170 °C, is catalyzed by [{Rh(µ-Cl)(1,5-cod)} 2 ] or [Rh(1,5-cod) 2 ][OTf] (0.5-1 mol % Rh) to give the linear compound Ph 2 PH-BH 2 -PPh 2 -BH 3 (1) at 90 °C, and a mixture of the cyclic trimer [Ph 2 P-BH 2 ] 3 (2a) and tetramer [Ph 2 P-BH 2 ] 4 (2b) at 120 °C. In addition, the catalytic potential of other (e.g., Ti, Ru, Rh, Ir, Pd, Pt) complexes toward the dehydrocoupling of Ph 2 PH‚BH 3 was investigated and was in many cases demonstrated. The molecular structures of 1 and 2b, and of the primary phosphine-borane adduct PhPH 2 ‚ BH 3 , were determined by single-crystal X-ray analysis. The dehydrogenative coupling of PhPH 2 ‚BH 3 gave low-molecular-weight poly(phenylphosphinoborane) [PhPH-BH 2 ] n (3) when performed in toluene (110 °C) with ca. 0.5 mol % [Rh(1,5-cod) 2 ][OTf] as catalyst. The absolute weight-average molecular weight was determined by static light scattering (SLS) in THF which showed that M w ) 5600. Samples of high-molecularweight polymer 3 (M w ) 31 000 or 33 300 by SLS) were synthesized using neat conditions at 90-130 °C in the presence of [{Rh(µ-Cl)(1,5-cod)} 2 ], anhydrous RhCl 3 , or RhCl 3 hydrate (ca. 1 mol % Rh). Poly-(phosphinoborane) 3 was thereby obtained in ca. 75% yield as an air-stable, off-white solid and was structurally characterized by 1 H, 11 B, 13 C, and 31 P NMR and IR spectroscopy and elemental analysis. The hydrodynamic diameters for polymers 3 in THF were also determined by dynamic light scattering (DLS). Catalytic dehydrocoupling of the alkyl-substituted phosphine-borane adduct iBuPH 2 ‚BH 3 was also investigated and was found to be much slower than that of PhPH 2 ‚BH 3 . This produced poly(isobutylphosphinoborane) [iBuPH-BH 2 ] n (4) under neat conditions at 120 °C in the presence of [{Rh(µ-Cl)(1,5-cod)} 2 ] in 80% yield. Multinuclear NMR spectroscopy and DLS were also used to characterize polymer 4, and the latter indicated that M w ) ca. 10 000-20 000. Prolonged heating of polymers 3 and 4 at elevated temperatures in the presence of catalyst led to insoluble but solvent-swellable gels possibly due to light interchain cross-linking through P-B bonds. In the absence of rhodium catalyst thermally induced dehydrocoupling of PhPH 2 ‚BH 3 and iBuPH 2 ‚BH 3 proceeds very slowly and forms only low-molecular-weight materials with complex NMR spectra and which probably possess a branched structure.

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“…Traditionally, the addition of alcohols to acetylenes needs strong bases under harsh conditions, and arylacetylenes were hydroalkoxylated in an anti-Markovnikov fashion to give β-arylvinyl ethers . Synthesis of enol ethers was also conducted by other methods such as cross-coupling of alkenyl halides with alcohols, elimination of alcohols from acetals, trans -alkenylation, Horner−Wittig and Tebbe olefinations, and catalytic substitution of α,β-unsaturated acetals with Grignard reagents . But the simplicity and the high atom economy of the hydroalkoxylation is desirable, and the use of transition metal catalysts has been examined.…”

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confidence: 99%

Rhodium-Catalyzed Anti-Markovnikov Intermolecular Hydroalkoxylation of Terminal Acetylenes

2010

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We report here the first transition-metal-catalyzed anti-Markovnikov intermolecular hydroalkoxylation of terminal acetylenes to give enol ethers in high yields without using bases. Arylacetylenes as well as alkenyl- and alkylacetylenes were coupled with aliphatic alcohols, and the products were obtained with high Z selectivity in most cases. Effective catalysts were 8-quinolinolato rhodium complexes, which are structurally simple but have been relatively unexplored as catalysts.

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Chlorotitanium Triisopropoxide

Cited by 3 publications

References 37 publications

Transition Metal-Catalyzed Formation of Boron−Nitrogen Bonds: Catalytic Dehydrocoupling of Amine-Borane Adducts to Form Aminoboranes and Borazines

Transition Metal-Catalyzed Formation of Boron−Nitrogen Bonds: Catalytic Dehydrocoupling of Amine-Borane Adducts to Form Aminoboranes and Borazines

Transition Metal-Catalyzed Formation of Phosphorus−Boron Bonds: A New Route to Phosphinoborane Rings, Chains, and Macromolecules

Rhodium-Catalyzed Anti-Markovnikov Intermolecular Hydroalkoxylation of Terminal Acetylenes

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