Boron tribromide-sodium iodide-15-crown

ESTERS Sodium benzeneselenolate. ETHERS Boron tribromide-Sodium iodide-15-Crown-5. Boron trifluoride etherate. Ferric chloride-Silica. Lithium iodide. Silicon(IV) chloride-Sodiuiu iodide. Sodium iodide-Pivaloyl chloride. 2,4,4,6-Tetrabromocyclohexadiene. Trichloro(methyl)silane. 

Reactions.—New methods for the synthesis and cleavage of benzyl and trityl ethers, and for the cleavage of allyl ethers have been discussed in an earlier section (Protection of Alcohols). Primary and secondary alkyl methyl ethers have been demethylated by the combination boron tribromide-sodium iodide-15-crown-5 The reagent methyltrichlorosilane-sodium iodide is a new combination for regioselective ether cleavage for example aliphatic methyl ethers undergo predominant demethylation to alcohols (for primary or secondary alkyl groups) or iodides (in tertiary cases). 

---