1.5- Dichloropentane, reaction with sodium

Lithium methanetellurolate and lithium or sodium arenetellurolates reacted with a,to-dibromoalkanes to produce a,m-bis[organotelluro]alkanes. The reactions with dihalomethanes leading to telluroacetals are discussed on p. 495. Several by-products are formed in these reactions, because halogen-metal exchange occurs followed by condensation reactions. With 1,4-dibromobutane or 1,5-dichloropentane, telluracycloalkanes are formed in appreciable yields2. 

Alkylation of sodium telluride with 1,5-dibromo- and 1,5-dichloropentanes serves as the most convenient one-step method of preparation of 1 (45JCS11). The yields of the reaction are 35-60%. 

The number of carbon atoms between two halides can vary, but monomers with five carbons may form a six-membered ring as a side product. For example, 1,5-dichloropentane in the presence of sodium sulfide forms cyclopentylsuflide (reaction 10)... 

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