Electrophilic Aromatic Substitution: Multi-Step Synthesis
Suggest a synthetic scheme for the conversion shown on the left. Work each problem backwards, and draw the structures of the two intermediates required for the conversion, and the reaction conditions necessary for each step.Click the mouse on the buttons to view the synthetic logic for each step, the structures of the intermediates and the solution to the problem.
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Working backwards, we are beginning with toluene and we are introducing a phenolic hydroxyl group and a chlorine. The chlorine is ortho- to the phenolic hydroxyl group, and since the para-position is blocked (by the methyl), the chlorine must have been put on last. Suggest a structure for the preceding intermediate and provide a method for its conversion into the final product.
Working backwards, we are beginning with toluene and we are introducing a phenolic hydroxyl group and a chlorine. The chlorine is ortho- to the phenolic hydroxyl group, and since the para-position is blocked (by the methyl), the chlorine must have been put on last. Next, suggest a synthesis of 4-methylphenol.
Phenol cannot be prepared directly from toluene using the reactions we have covered thus far. Phenol can be prepared, however, by the "alkali fusion" of the corresponding sulfonic acid.
Phenol cannot be prepared directly from toluene using the reactions we have covered thus far. Phenol can be prepared, however, by the "alkali fusion" of the corresponding sulfonic acid. Next, suggest a synthesis of para-toluenesulfonic acid, beginning with toluene.
Toluene is first sulfonated by reaction with fuming sulfuric acid (SO3/H2SO4). In a second step, this is converted to phenol by the "alkali fusion" reaction. Phenol is then chlorinated to give the desired product.