Methyl Ester Function: An Intramolecular Electrophilic Trap for the Isolation of Aryltellurenyl Hydroxide and Diorganotellurium Dihydroxide

The formation of an aryltellurenyl hydroxide analogue proposed in the telluroxide elimination reaction has been studied. The reaction of the monotelluride dimethyl 5-tert-butyl-2-(butyltellanyl)isophthalate (6) with H2O2 afforded the corresponding aryldiacyloxy-n-butyltellurane (8). The reaction of 6 with oxygen in the presence of moisture resulted in the formation of 8 as the major product along with traces of dimethyl 5-tert-butyl-2-(butyltellurinyl)isophthalate (7) and methyl 5-tert-butyl-3-oxo-3H-benzo[c][1,2]oxa tellurole-7-carboxylate (9). The telluroxide intermediate 7 readily undergoes a facile elimination reaction to give the elusive aryltellurenyl hydroxide, which is immediately trapped by the adjacent methyl ester functionality to give the cyclic tellurenate ester 9. Similarly, the hydrolysis of 7 with H2O affords the corresponding dihydroxytellurane 10, which is immediately converted to tellurane 8. Both compounds 8 and 9 have been characterized by single-crystal X-ray crystallographic studies.