The reaction of phenylethanone with 1,4-dibromobutane, $$\(\mathrm{BrCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}\)$$, in the presence of $$\(\mathrm{FeBr}_{3}\)$$ is shown in Fig. 6.2. The mechanism of this reaction is similar to that of the alkylation of benzene. (i) Construct an equation for the formation of the electrophile, $$\(\mathrm{BrCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2}{ }^{+}\)$$. ................................................................................................................................. (ii) Complete the mechanism in Fig. 6.3 for the reaction of phenylethanone with $$\(\mathrm{BrCH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2}^{+}\)$$ions. Include all relevant curly arrows and charges. Draw the structure of the organic intermediate. (iii) The reaction shown in Fig. 6.2 forms small amounts of two by-products, $$\(\mathbf{Y}\left(\mathrm{C}_{20} \mathrm{H}_{22} \mathrm{O}_{2}\right)\)$$ and $$\(\mathbf{Z}\left(\mathrm{C}_{12} \mathrm{H}_{14} \mathrm{O}\right)\)$$. Suggest structures for $$\(\mathbf{Y}\)$$ and $$\(\mathbf{Z}\)$$ in the boxes in Fig. 6.4.

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