In my school, you won't do well in orgo 3 if you haven't taken orgo 1 and 2, but you can take orgo 2 without taking orgo 1.
Quarter system.
So that doesn't really help you...
Yeah we have semester system.
The first course was pretty much nomenclature, functional groups, isomers, chair flips, sn1, sn2, e1, e2, alk(a,e,y)nes, alchol, ethers, aldehydes, ketones, others. Basically concepts and things that aren't mentioned below.
The second course was mainly aromatics (ortho, meta, para), carboxylic acids and derivatives, carbohydrates, and amino acids. Seemed like 70% of this course had something to do with carboxylic acids and their derivatives. Also grignard, diels alder, aldol, wittig.
I guess after writing it out it seems like it could be 50/50... who knows.