Dibutyl telluroxide

Catalytic one-pot procedure. Since in the described teUuronium ylide olefmation tellurox-ide is formed as a by-product, and the telluroxide is susceptible to reduction by triphenyl phosphite, a catalytic procedure can be employed, providing a practical one-pot synthesis of a, -unsaturated esters and ketones (method E). By this procedure, a catalytic amount of n-dibutyl telluride reacts with the a-bromoester or a-bromoketone, and the formed tel-luronium salt is converted in situ under phase transfer conditions (solid KjCOj/trace HjO) into the ylide, which reacts in turn with the aldehyde, giving the olefin. Since the reaction is performed in the presence of triphenyl phosphite, the formed dibutyl telluroxide is reduced back to the dibutyl telluride, which is then recycled. 

Tellurium-Wittig reactions.1 The reaction of aldehydes with a-bromo esters or ketones, triphenyl phosphite, and a weak base in the presence of a catalytic amount of Bu2Te results in ct, l-unsaturated esters and ketones. The function of the triphenyl phosphite is the regeneration of Bu2Te from the dibutyl telluroxide formed in the... 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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