Trityl sodium

Trityl sodium is an extremely strong base, being soluble in ethers and aromatic hydrocarbons to give deep blood-red solutions so that in titration of an acid it can serve as its own visual indicator, although potentiometric detection is also possible a disadvantage is its high sensitivity to oxygen and moisture. 

The chiral heterocycle (81) is deprotonated by trityl sodium and the resulting anion trapped with methyl formate giving the hydroxymethylene derivative (82) <92JCS(P1)517>. 

A somewhat different situation was found to prevail in the butadiene polymerization initiated by trityl sodium (102). The deep red color of trityl sodium does not disappear upon addition of monomer, but remains the same throughout the polymerization. This phenomenon was shown to be due to an opposite difference in rates than that found in the butyllithium case, namely... 

If the initiation reaction is many times slower than the propagation reaction essentially no trityl sodium will be consumed. The validity of this scheme was shown by trapping the product of the initiation reaction with diethylamine (a compound which does not react with trityl sodium). In the presence of diethylamine then, sodium... 

This was readily verified (Scheme 4). Thus Normant and Cuvigny12 prepared trityl sodium in HMPA by reaction of triphenylmethane with NaNH2. With similar conditions but in THF, this reaction is not obtained. On the contrary in this latter solvent, if the base used is NaNH2 -r-BuONa, the deep red color of the anion immediately appears at room temperature10, n However, the transformation is not quantitative (vide infra). 

Polymerization catalysts Dibenzoyl peroxide. Diisopropyl peroxydicarbonate. Trityl-sodium. 

Acetylation Acetic anhydride. N-Acetoxyphthalimide. 2- and 3-Acetoxypyridine. Acetyl chloride. N-Acetylimidazole. Boron trifluoride. Catalysts (see Acetic anhydride). Ketene. Magnesium. Methyl oxocarbonium hexafluoroantimonate. Perchloric acid. Phenyl acetate. Pyridine. Sodium acetate. Tetraelhylammonium acetate. p-Toluenesulfonic acid. Tri-n-hexylethyl ammonium hydroxide. 2,4,6-Triisopropylbenzenesulfonyl chloride. Trityl-sodium. Zinc chloride. 

In 1952, Wittig and Fritz reported that treatment of a triphenylsulfonium salt with phenyllithium afforded directly diphenylsulfide (3) and biphenyl (4). They also showed that treatment of the triphenylsulfonium salt with trityl sodium led to tetraphenylmethane, although in poor yield. Later, in 1962, Sheppard described the reaction of phenyllithium with phenylsulfur trifluoride or with sulfur tetrafluoride at - 80 C, which afforded biphenyl and diphenylsulfide. At the same time, Franzen et al. suggested that a tetracoordinate sulfurane was intermediately formed and collapsed to lead to the ligand coupling products. i... 

In a water-free medium chain growth polymerization can be initiated by numerous metal-organic or basic compounds, such as trityl sodium [81], butyl lithium [80,81], naphthyl sodium [80,81], benzophenone potassium [81], sodium methoxide [80,81], lithium organocuprates [85] and rhodium(I) complexes [86] or ammonia [87], er -phosphines [80,88], aliphatic amines [89], cyclic amines [90], and aromatic amines (pyridine [91,92],... 

In practice the various trityl derivatives are cleaved with acid, but the monomethoxy derivative can be cleaved with sodium naphthalenide in HMPA (90% yield).It is not cleaved by sodium anthracenide, used to cleave a-naphthyldi-phenylmethyl ethers. 

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... 

B. Das, G. Mahender, V. S. Kumar, and N. Chowdhury, Chemoselective deprotection of trityl ethers using silica-supported sodium hydrogen sulfate,... 

The interesting observation has been made that, although treatment of N6-trityl-5 -0-trityladenosine with benzyl chloride-sodium... 

Starting with the same acetal (35), but proceeding by way of the diacetate 40, instead of the dibenzoate 36, it was possible to prepare,51 in high yield, the p-toluenesulfonate 41 by sequential trityla-tion and p-toluenesulfonylation. Compound 41 was then subjected to solvolysis in the presence of sodium acetate in moist N,N-dimethyl-formamide, and the product (42) was successively acetylated and de-tritylated to give 3,4,6-tri-0-acetyl-2,5-anhydro-D-allitol (43). The... 

Ohrui and Fox128 reported that treatment of 2,3-O-isopropylidene-5-O-trityl-jS-D-ribofuranosyl chloride (171) with diethyl sodiomalonate in 1,2-dimethoxyethane gave an anomeric mixture of C-glycosyl compounds (172) which, when allowed to equilibrate in ethanol containing sodium ethoxide, gave the )3 anomer (173) as the preponderant product. Similar observations were made with the C-... 

Ohrui and Fox128 obtained the sodium salt of 5-(2,3-0-isopropylidene-5-0-trityl-/3-D-ribofuranosyl)barbituric acid (271) by treatment of the corresponding C-malonyl derivative (173) with urea... 

Pyrroline-A-oxide (258) is isomerized into y-lactam (259) in the presence of lithium diisopropylamine (LDA) (470) and sodium trityl (471). In these reactions, deprotonation at C3 occurs, leading to carbanion (260). Then oxygen migration from Ni to C2 takes place via intermediate formation of oxaziridine... 

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