Answer
The 1,2-dimethylcyclohexene can be converted into the product in 8-46(c) and then $KO- t-Bu_2$ can be used to synthesize the desired product.
Work Step by Step
$Br_2$ adds trans Br across the double bond. Then $KO- t-Bu_2$ can be used to do E2 and form the double bonds by kicking out the bromines.