Tellurinylated cyclic ethers

Aryltellnrinyl acetates, generated as previously described from the corresponding tellurinic anhydrides and acetic acid, add to hydroxy olefins, giving tellurinylated cyclic ethers. The reaction is performed in refluxing acetic acid or in chloroform in the presence of BFj EtjO. Owing to their hygroscopicity and intractable nature, the products are reduced with hydrazine hydrate, and isolated as tellurides (as for the aminotellurinylation reactions). 

When the olefin has a hydroxyl group in a y- or (5-position to the double bond, the addition of the tellurinyl acetate is accompanied by the formation of cyclic ethers. The cyclization reactions compete with the formation of the linear addition products shown in the preceding equation. 

---