I only glanced at EK when I was doing my prep, so I can't say for sure, but my guess is because many of those reactions are not tested by the MCAT. Alkenes, for instance, are off limits.
Little-known fact: if you go to the official MCAT/AAMC website, they actually list outlines of the subjects tested by the MCAT....the orgo one is especially worth checking since a lot of topics you'd expect to be tested are not, and you'll save yourself a lot of time.