Hydroxyalkenes to Brominated Cyclic Ethers

3-(2 -Hydroxyethyl)cyclopent-l-ene and benzenetellurinyl acetate formed an addition product containing a cyclic-ether functionality. This intermediate was reduced to the telluride, the telluride converted to the tellurium dibromide, and the dibromide heated in dimethylformamide with sodium bromide to give the brominated cyclic ether.  

A reaction sequence starting with bis[phenyltelluro]methane leads to the insertion of a methylene group into the carbon-halogen bond of an alkyl halide. The bis[phenyltelluro] methane is reacted with butyl lithium to yield lithiomethyl phenyl telluride, which combines with an alkyl halide. The resulting alkylmethyl phenyl tellurium is converted to the tellurium dihalide, which in turn decomposes to an alkylmethyl halide when kept under vacuum at 250 or heated in DMF in the presence of a sodium halide at 100°.  

Decomposition of Hexadecyl Phenyl Tellurium Dichloride in DMF A stirred suspension of 0.2 g (0.40 mmol) hexadecyl phenyl tellurium dichloride, 30 mg (0.51 mmol) of sodium chloride, and 2 ml of DMF is heated under nitrogen at 100 for 1 h. The mixture is then allowed to cool to 20°, is poured into water, and extracted with hexane. The extract is dried with anhydrous magnesium sulfate and filtered through a short column of silica gel. The solvent is evaporated to leave I-cMorohexadecane as a colorless oil yield 96 mg (92%). 

Decomposition of Dodecyl Phenyl Tellurium Dibromide under Vacuum 0.53 g (1.0 mol) of dodecyl phenyl tellurium dibromidc is placed in a Kugelrohr distillation apparatus and is heated at 230-250°/3 torr. The colorless liquid distillate is dodecyl bromide-, yield 0.25 g (90%). 

2-phenylethyl bromide yield 80% tetradecyl bromide yield 98% 

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