A NEW METHOD FOR THE WILLIAMSON ETHER SYNTHESIS USING T-ALKYL HALIDES IN NONPOLAR-SOLVENTS

It is a well-known result that the reactions of t-alkyl halides with alkali metal aryl oxides and alkoxides in protic solvents give olefins(E) almost exclusively. By contrast, we found a new method for the Williamson ether synthesis in the reactions of t-alkyl halides with alkali and alkaline earth metal phenoxides and alkoxides at 60-90 degrees C in nonpolar solvents(hexane and heptane). The yields of t-alkyl phenyl ethers and t-butyl alkyl. ethers(SN) were moderate. The selectivity of SN/E was governed by solvent, metal cation (Li+, Na+, K+, Mg2+, Ca2+, Sr2+ and Ba2+), nucleophile, and substrate. The nonpolar solvents were much more effective for the SN reaction than polar solvents.