A normal C-C disconnection is also a possibility, but disconnection to the `natural' a' synthon
and the umpolung dl is necessary. One very useful umpotung reagent is cyanide, arid you can see it
in action in this synthesis of the tranquillizer phenaglycodol. The tertiary alcohol with two R groups
the same should prompt you to think of doing a double Grignard addition to an ester. FGI then
reveals the nitrite functional group necessary for a 1,2-diX disconnection to cyanide plus ketone.