Sodium tetrakis

It is liquefied by conducting the gas through a condenser cooled with ice water. Where difficult to obtain, it may be prepared by passing chlorine gas through a stirred suspension of sodium tetrakis(cyano-C)zincate prepared in situ from sodium cyanide and zinc sulfate. ... 

Experience in PTC with cationic catalysts showed that, in general, the most suitable compounds have symmetrical structures, are lipophilic, and have the active cationic charge centrally located or sterically shielded by substituents. For anionic catalysis sodium tetraphenylborate fulfills these conditions, but it is not stable under acidic conditions. However, certain derivatives of this compound, namely sodium tetra-kis[3,5-bis(trifluoromethyl)phenyl]borate (TFPB, 12.162) and sodium tetrakis[3,5-bis-(l,l,l,3,3,3-hexafluoro-2-methoxy-2-propyl)phenyl]borate (HFPB) are sufficiently stable to be used as PTC catalysts for azo coupling reactions (Iwamoto et al., 1983b 1984 Nishida et al., 1984). These fluorinated tetraphenylborates were found to catalyze strongly azo coupling reactions, some of which were carried out with the corresponding diazotization in situ. 

The formation of ethers such as 1806 by EtsSiH 84b can also be catalyzed by trityl perchlorate to convert, e.g., benzaldehyde in 84% yield into dibenzyl ether 1817 [48]. The combination of methyl phenethyl ketone 1813 with O-silylated 3-phenyl-n-pro-panol 1818, in the presence of trityl perchlorate, leads to the mixed ether 1819 in 68% yield [48] (Scheme 12.15). Instead of trityl perchlorate, the combination of trityl chloride with MesSiH 84a or EtsSiH 84b and sodium tetrakis[3,5-bis-(trifluoro-methyl)phenyl]borane as catalyst reduces carbonyl groups to ethers or olefins [49]. Employing TMSOTf 20 as catalyst gives very high yields of ethers. Thus benzaldehyde reacts with O-silylated allyl alcohol or O-silylated cyclohexanol to give the... 

Amino acids may be determined by measuring the amines obtained after the action of a carboxylase with a specific electrode for amines, which is based on a poly(vinyl chloride) membrane containing sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (166) as ion exchanger and tricresyl phosphate as solvent mediator. LOD was 20 and 50 i-M for tyroxine and phenylalanine, determined as tyramine (5) and phenethylamine (33), respectively364. 

SODIUM TETRAKIS(3,5-BIS(TRIFLUOROMETHYL) PHENYL)BORATE, Na[B(3,5-(CF3)2C6H3)4]... 

Sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBArp) (227 mg, 0.243 mol) Water (3 mL, degassed)... 

If the solid obtained here is allowed to stand in contact with a little concentrated sodium carbonate solution for several hours, the cobalt is converted to reddish cobalt carbonate and the colorless supernatant liquid contains sodium tetrakis(thiocyanato)mercurate (II). 

Tris(trimethylsilyl)aluminum, AllSifCHOj] (1). The reagent is obtained as the THE complex by reaction of Hg(Si(CH,),]i with aluminum powder in THE (90% yield). Nonsolvated reagent is prepared by reaction of sodium tetrakis(trimethylsilyl)aluminate with AlCl, in pentane. It ignites spontaneously in air dec. at 50°."... 

The easiest reactions are those in which the nucleophile is the gold-activated species. Examples of this are Au(I)-catalyzed carbene and nitrene transfers (equations 142 and 143) that convert olefins into cyclopropanes or aziridines, respectively. In the carbene transfer, ethyl diazoacetate is the source of carbene and the active NHC-gold cationic catalyst is generated by chloride abstraction with sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate NaBAT4. The cyclopropanation is competitive with other carbene insertions with active C H or N H bonds present in the substrate. For the aziridinations of olefins, nitrene formation is accomplished by the oxidation of sulfonamides with PhI(OAc)2 and the catalyst of choice is a gold-(I) triflate with a terpyridine ligand. 

The silyl organoaluminum reagent (52) was prepared either by the addition of activated aluminum to a tetrahydrofuran solution of chlorotrimethylsilane, or by the treatment of sodium tetrakis(trimethyl-silyl)aluminate with aluminum chloride. Alternatively, ate complex (53) may be prepared by the addition of methyllithium to tris(trimethylsilyl)aluminum. ... 

A complementary, but less pronounced, increase in cis syri) selectivity is provided when diazoacetates with rather small ester groups and rhodium catalysts with bulky ligands, such as iodorhodium(IIl) porphyrins and mcso-tetrakis(2,4,6-triarylbenzoato)di-rhodium(ll) complexes, are employed. For ethyl 2-alkylcyclopropane-l-carboxylates so obtained, a cisfran.s ratio of 2-4 was typical. Notable cis selectivities have also been achieved in the synthesis of ethyl 2-phenylcyclopropane-l-carboxylate with the catalyst [(r/ -C5H5)Fe(CO)2(THF)][BFJ (cis/trans 5.25, see Section 1.2.1.2.4.2.6.3.1.) and copper catalysts prepared in situ from a copper salt [copper(I) iodide, copper(II) acetate or triflate] and sodium tetrakis(7,8,8-trimethyl-4,5,6,7-tetrahydro-2Ff-4,7-methanoindazolyl)borate (3) cis/ trans 2.1-3.2). °... 

The vast literature on applications of PTC in substitution reactions is mainly restricted to nucleophilic substitution reactions with an anionic reagent. However, recently the use of PTC in electrophilic reactions, like diazotization andazocou-pling C-and N-nitrosation, C-alkylation, acid hydrolysis of esters, chloromethylation, nitrite-initiated nitrations, and so on have been reported(Velichko et al., 1992 Kachurin et al., 1995). Alkylbenzene sulfonates and lipophilic sodium tetrakis[3,5-bis(trifluoromethyl)phenylboranate are typical electrophilic PT catalysts. Lipophilic dipolar molecules of the betaine type and zwitterionic compounds also function well as PT agents for both nucleophilic as well as electrophilic reactions. 

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