Which of the following retrosynthetic disconnections is most appropriate for synthesizing $p_{-}\mathrm{nitroaniline}$ from readily available starting materials?

Which of the following statements best describes the purpose of retrosynthesis in organic chemistry?

Given the target molecule ${\mathrm{Ph}}_2\mathrm{CO}$ (benzophenone), which of the following disconnections leads to the most reasonable retrosynthesis?

Supply the reagents necessary to accomplish the following transformation.

Supply the reagents necessary to accomplish the following transformation.

Compound A (C₇H₁₁Br) is treated with magnesium in ether to give B (C₇H₁₁MgBr), which reacts violently with D₂O to give 1-methylcyclohexene with a deuterium atom on the methyl group (C). Reaction of B with acetone (CH₃COCH₃) followed by hydrolysis gives D (C₁₀H₁₈O). Heating D with concentrated H₂SO₄ gives E (C₁₀H₁₆), which decolorizes two equivalents of Br₂ to give F (C₁₀H₁₆Br₄). E undergoes hydrogenation with excess H₂ and a Pt catalyst to give isobutylcyclohexane. Determine the structures of compounds A through F, and show your reasoning throughout.

Show how you would convert the following starting materials into the target compound. You may use any additional reagents you need.

Using any necessary inorganic reagents, show how you would convert acetylene and isobutyl bromide to

(b) (±)-2,7-dimethyloctane-4,5-diol.