Tritylone ethers

The p-cyanobenzyl ether, prepared from an alcohol and the benzyl bromide in the presence of sodium, hydride (74% yield), can be cleaved by electrolytic reduction (—2.1 V, 71% yield). It is stable to electrolytic removal ( — 1.4 V) of a tritylone ether [i.e., 9-(9-phenyl-10-oxo)anthiyl ether]. ... 

Phenyl-10-oxo)anthryl Ether (Tritylone Ether) (Chart 1) ... 

The tritylone ether is used to protect primary hydroxyl groups in the presence of secondary hydroxyl groups. It is prepared by the reaction of an alcohol with 9-phenyl-9-hydroxyanthrone under acid catalysis (cat. TsOH, benzene, reflux, 55-95% yield).It can be cleaved under the harsh conditions of the WolfT-Kishner reduction (H2NNH2, NaOH, 200°, 88% yield), " and by electrolytic reduction (-1.4 V, LiBr, MeOH, 80-85% yield). It is stable to 10% HCl, 55 h. ... 

Tritylone alcohol reacts readily with alcohols to give tritylone ethers. Selective reaction of primary alcohols in the presence of secondary alcohols is possible. These new ethers are more stable to acid than trityl ethers. They can be cleaved by Wolff Kishner reduction. ... 

Tritylone ethers (57), used as acid-stable protecting groups for alcohols, are cleaved under Wolff-Kishner (Huang-Minlon) conditions as the unblocking step. ... 

The suitability of tritylone ethers as protecting groups for alcohols has been explored, with cholesterol among model alcohols.The ether (134) was formed from tritylone alcohol and cholesterol under acidic conditions with azeotropic... 

The formation of triphenylmethyl (trityl) ethers from trityl chloride and primary or secondary alcohols is another reaction now found to be catalysed by DMAP. In this procedure, as with the silylation reported above, stoicheiometric triethylamine is used to regenerate the DMAP. Tritylone ethers (60) are more... 

The utility of but-2-enyl ethers as alcohol protecting groups has been described the function is stable to mild acid and base, but is readily cleaved by potassium t-butoxide in DMSO at room temperature. A full description of the use of tritylone ethers as protecting groups has been published. 

Tritylone ethers s. 9-Anthronyl ethers, 9-phenyl-Trop... s. a. Cycloheptatrien... Tropenium salts... 

An alcohol protecting group cleavable by specific base catalysis is offered as an alternative to the more common acid-labile functions. Tritylone ethers... 

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