Allyldiisobutyltelluronium bromide

Allyldiisobutyltelluronium bromide (0.87 g, 2.4 mmol) and KOt-Bu (0.269 g, 2.4 mmol) are placed in a reaction vessel under Nj, and dry THF (4 mL) is added with stirring at -78°C. After a few minutes, a solution of benzaldehyde (0.216 g, 2 mmol) in THF (2 mL) is added dropwise, and the reaction mixture is slowly allowed to warm to room temperature. Normal work-up followed by SiOj column chromatography gives diisobutyl telluride (0.55 g (95% based on the used salt) eluted by hexane) and 2-phenyl-3-vinyloxirane (0.356 g (82%) cisitrans = 85 15 eluted by 5% ether/hexane). 

Typical procedure A mixture of p-chlorophenol (128 mg, 1 mmol), NaOH (40 mg, 1 mmol) and THF (10 mL) was stirred for 10 min allyldiisobutyltelluronium bromide (360 mg, 1 mmol) was then added. The reaction mixture was stirred for another 5 h at room temperature under nitrogen. Aqueous saturated NaHCOj solution was added and extracted with CH2CI2. The extract was dried over anhydrous MgS04 and concentrated in vacuo. The residue was chromatographed on silica gel with 95 5 hexane-ethyl acetate as eluent to give a colourless oil of allyl p-chlorophenyl ether (145 mg, 86%). 

By contrast, 4-chlorophenol undenA ent etherificatbn when reacted in tetrahydrofuran solution containing 1 mole of sodium hydroxide with allyldiisobutyltelluronium bromide under nitrogen during 5 hours to give allyl 4-chlorophenyl ether in 86% yield (ref. 41). 

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