Only one combination of alkyl halide and alkoxide is appropriate for the preparation of ea...

Only one combination of alkyl halide and alkoxide is appropriate for the preparation of each of the following ethers by the Williamson ether synthesis. What is the correct combination in each case?

(b) H2C=CHCH2OCH(CH3)2

(c) (CH3)3COCH2C6H5

Sample Solution (a) The ether linkage of cyclopentyl ethyl ether involves a primary carbon and a secondary one. Choose the alkyl halide corresponding to the primary alkyl group, leaving the secondary alkyl group to arise from the alkoxide nucleophile.

The alternative combination, cyclopentyl bromide and sodium ethoxide, is not appropriate because elimination will be the major reaction: