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, this molecule is 2,4,6-trinitrophenol, and we must begin with benzene. The phenol group is very strongly activating and ortho-para- directing, so the desired product could be prepared by nitration of phenol. Suggest a method for the conversion of phenol to the final product.

Working backwards, this molecule is 2,4,6-trinitrophenol, and we must begin with benzene. The phenol group is very strongly activating and ortho-para- directing, so the desired product can be prepared by nitration of phenol. Next, suggest a synthesis of phenol.

Phenol cannot be prepared directly from benzene using the reactions we have covered thus far. Phenol can be prepared, however, by the "alkali fusion" of benzene sulfonic acid.

Phenol cannot be prepared directly from benzene using the reactions we have covered thus far. Phenol can be prepared, however, by the "alkali fusion" of benzene sulfonic acid. Next, suggest a synthesis of benzenesulfonic acid, beginning with benzene.

Benzene 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 exhaustively nitrated to give the desired product.