Note that these types of questions are often the most difficult on the examination. This is because they are holistic in that they require a good understanding of the reactions and the concepts and the ability to apply those concepts. They can't be memorised, they require understanding and ability to apply. Hence they help discriminate those who truly understand from those who have memorised and will soon forget.

A schematic of the solution is shown below. The information from the question is given in black. Deductions directly from this information are given in red. Points that provide potential key information are shown in green which leads to the structures which are linked via the blue arrows to show the path required to work them all out. There are, of course, other possible thought pathways.

The diagram gives the completed solution with the structures in blue. Key steps are drawing the named structure and hence back to D and the formation of the ether from the alcohol / alkyl bromide in F.

D has two stereocenters (one cis- or trans- C=C and one R or S chirality center) and therefore has 2ⁿ = 2² = 4 configurational isomers.

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