Sodium tellurocarboxylate

Coupling sodium tellurocarboxylates with R SiCl gives the unstable silyl derivative which isomerizes to the more thermodynamically stable RC(Te)OSiR 3 through a facile rearrangement that can be readily followed by 13C NMR spectroscopy. This contrasts with the reaction of alkali metal thiocarboxylates which give the O-silyl ester directly. There is no evidence for the S-silyl intermediate101. 

The red, oily sodium tellurocarboxylates (p. 162) react with an excess of an alkyl iodide at temperatures between — 63 and — 30° to give alkyl tellurobenzoates, yellow to orange oils or crystals, that are relatively stable thermally and hydrolytically. They can be stored at — 20° under argon for weeks but they are very sensitive towards oxygen. The methyl tellurobenzoates are the least stable of the tellurobenzoates1,2. 

A large number of stable /e-organo tellurocarboxylates were prepared from tellurolates and aliphatic1,2 or aromatic2 carboxylic acid chlorides or aliphatic carboxylic acid anhydrides . The tellurolates were obtained by reduction of diorgano ditelluriums with sodium borohydride. 

From Sodium or Piperidinium Tellurocarboxylates and Alkyl Iodides... 

Only a few representatives of tellurocarboxylic acid anhydrides have been prepared from tellurium, sodium telluride, or bis[trimethylsilyl] tellurium and alkanoyl or arenoyl chlorides. Diacyl telluriums are stable at 20°, however, they are very sensitive to air and moisture. 

Te-Esters of tellurocarboxylic acids were prepared from tellurolates and carboxylic acid chlorides or anhydrides, and from sodium telluride and aroyl chlorides". The following types of 7e-organo tellurocarboxylates have thus far been synthesized ... 

The authors also synthesized tellurol esters by successive acylation and alkylation of sodium telluride (Na2Te) via tellurocarboxylates [115]. Suzuki, Tani and co-workers succeeded in the synthesis of tellurol esters by a similar method using sodium hydrogen telluride (NaTeH) (Eq. 60) [116]. 

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