How many of the following ethers CANNOT be prepared by Williamson's synthesis? CH 3 OCH 2 CH 3 , C 6 H 5 OCH 3 , ( C 6 H 5 ) 2 O , ( CH 3 ) 3 COCH 3 , ( C 2 H 5 ) 2 O , ( CH 3 ) 3 C - O - C ( CH 3 ) 3

Step-by-step solution

In Williamson's synthesis, i. 1 ° alkyl halide and 3 ° alkoxide give best yield of corresponding ethers. ii. In case of, 3 ° alkyl halide, elimination competes over substitution and alkene is obtained as a product. iii. Aryl halides do not undergo nucleophilic substitution unless it is activated by the presence of electron withdrawing group. Thus, ( C 6 H 5 ) 2 O and ( CH 3 ) 3 C - O - C ( CH 3 ) 3 cannot be prepared by Williamson's synthesis.