Tris pentafluorophenyl Borane

Another related boron Lewis superacid, B (CF3)3, is worth mentioning, even though it has not been isolated.59 However, the corresponding anion B(CF )i is known and 

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Imidazole reacts with dimethylzirconocene in the presence of a strong Lewis base, tris(pentafluorophenyl)borane, to yield the betaine species 22 (96JOM(518)17), which when exposed to the atmosphere is hydrolyzed to 23. 

Activation Using Tris(pentafluorophenyl)borane as the Lewis Acid. 64... 

More recently, a novel metal-substituted methylenecyclopropene (triafulvene) derivative was obtained when bis(propyne)zirconocene was treated with one equivalent of tris(pentafluorophenyl)borane, followed by excess of benzonitrile (equation 367)430. The first step involves alkynyl ligand coupling to give the isolable Cp2Zr(//-2,4-hexadiyne)B(C6F5)3 betaine. This undergoes a formal intramolecular nitrile insertion into the Zr—C(sp2) c-bond of the adjacent alkenyl zirconocene unit, leading to the zirconium-boron triafulvene-betaine. X-ray analysis of the triafulvene confirmed the planar... 

A one-pot reaction has been developed for the reduction of aldehydes, ketones, and primary, secondary and tertiary alcohols into their corresponding alkyl function using either diethylsilane or n-butylsilane as the reducing agent in the presence of the Lewis acid catalyst tris(pentafluorophenyl)borane carbon-carbon double bonds remain unaffected.366 Aliphatic and aromatic polycarboxylic acids are also conveniently reduced to their corresponding alkanes using the same reagents and catalyst.367... 

Methylaluminoxane-free catalysts, such as cationic complexes derived from TiBz4 and tris(pentafluorophenyl)borane [B(C6F5)3], appear to be much less active, poorly stereospecific catalysts for the polymerisation of styrene. Under analogous conditions, the use of N, yV-dimethylanilinium tetrakis(pentafluor-ophenyl)borate [Me2N(Ph)H]+[B(C6F5)4]- instead of B(C6F5)3 does not yield active catalysts only traces of syndiotactic polystyrene were obtained [70]. 

Copoly condensation of Functional Silanes and Siloxanes in Solution Using tris(pentafluorophenyl)borane as a Catalyst in a View to Generate Hybrid Silicones... 

Tris(pentafluorophenyl)borane [B(CgFj)3], is a powerful and selective Lewis acid catalyst used in many reactions in organic chemistry [1 ]. Parks and Piers [5] found that B(CgFj)3 catalyzes the hydrosilylation of carbonyl compounds. The silylation of alcohols with the formation of Ft as the only by-product [6] and the cleavage of silyl ether and ether bonds catalyzed by B(C F5)3 [7, 8] provide an... 

Tris(pentafluorophenyl)borane (BCCgFj), purity 97%) was obtained from Lancaster, dimethoxydimethylsilane (DMDMS) from PCR, 1,1,3,3-tetramethyldisiloxane (L H, purity 97%) from ABCR, the methoxydimethylsilane (MDMS) from Fluorochem and 1,7-octadiene (purity 98%) from Aldrich. AU of them were used without any further purification. All solvents were pnrchased from Aldrich and anhydrons tolnene was stored over sodium. During the varions experiments we used two batches of catalyst. Since the first one contained a fair amonnt of water, a small content of Brij 98 (from Aldrich), a non-ionic surfactant, was added, so that the ethylene glycol functions competed with water to complex B(C Fj)3 and to increase its activity. 

The construction of a borole ring that is part of a metal complex from zirconium-coordinated 1,3-dienes and tris(pentafluorophenyl)borane has been recently introduced. Tris(pentafluoro-phenyl)borane is widely used as an activator of metallocene-based polymerization catalysts because of its resistance to aryl-transfer reactions, it acts as the boron source. The reaction utilizes the zwitterionic 14-electron bis(allyl)zirconium complexes 72 and 73 which are converted to the corresponding complexes 74 and 75 via activation of one of the C-H bonds of the B-CH2 moiety... 

Wang [3] polymerized ethylene using boron containing activators tris(penta-fluorophenyl)-borane, (II), and lithium tetrakis(pentafluorophenyl)borate, (III). Using tris(pentafluorophenyl)-borane, (II), with alumoxane, Arriola [4] prepared poly(ethylene-co-propylene) and polypropylene. 

A similar complex was obtained by treatment of s-cis-rj -butadiene)(cot)zirconium with tris(pentafluorophenyl)borane (equation 23). As for (55), the complex (56) shows an internal Zr-C ion pair and gives rise to a five-membered... 

A stable organometalhc C2v methane derivative (59) was obtained starting from the (/u.-vinyl)bis(zirconocene) complex with tris(pentafluorophenyl) borane. ... 

Lee, L.W.M., Piers, W.E., Elsegood, M.R.J. et al. (1999) Synthesis of dialkylscandium complexes supported by P-diketiminato ligands and activation with tris(pentafluorophenyl)borane. Organometallics, 18, 2947. 

Tris(pentafluorophenyl)borane, a compound first made by Stone et al. in 1963, has in recent years become one of the most widely applied boron reagents, as a highly effective activator for metallocene-based olefin polymerisation catalysts. There are several reasons for this it is a strong Lewis acid, unlike boron trihalides it is resistant to hydrolysis, and it possesses strong B-C and C-F bonds which make it essentially inert to chemical attack for example, it can be recovered unchanged from neat elemental bromine. 

Tris(pentafluorophenyl)borane, known as "FAB" (structure below), is the most common arylborane used as cocatalyst for single site catalysts. FAB is a strongly Lewis acidic, air-sensitive solid (T 126-131 °C) that is only slightly soluble in hydrocarbon solvents. The structure of FAB is given below. 

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