Hydroxyalkenes to Cyclic Ethers

4-Methoxyphenyl tellurium trichloride will effect the same transformation. Alkyl aryl tellurium dichlorides are intermediates in these reactions.  

5-Dimethyl-3-ethoxycarbonyltetrahydrofuran was similarly prepared from 4-ethoxycarbonyl- 5-hydroxy-1 -hexene.  

4-Methoxyphenyl tellurium trichloride adds to the carbon-carbon double bond of y-carboxy-l-alkenes. The intermediate aryl alkyl tellurium dichlorides are reduced to lactones.  

The following lactones were similarly prepared from the appropriate unsaturated carboxylic acids.  

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