Strategy I The Order of Events

Background Needed for this Chapter Reference to Clayden, Organic Chemistry  

Electrophilic aromatic substitution chapter 22. (Electrophilic Aromatic Substitution) 

Alternating with instructional chapters, like the last one, will be strategy chapters, like this one, which discuss reasons for choosing one route rather than another in other words the overall plan rather than the individual steps. In this chapter we shall examine the order of events, using the synthesis of aromatic compounds as examples. The details are specific but the guidelines general. 

Guideline 1 Consider the effects of each functional group on the others. Add first (that is disconnect last) the one that will increase reactivity in a helpful way. So, for aromatic compounds, introduce first that group that helps, by reactivity or direction, the introduction of the others. 

The synthesis1 is straightforward providing we alkylate first and acylate second. The branched alkyl group in 4 ensures that the para-ketone 1 will be the main product by steric hindrance. 

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