Thursday, February 24, 2011

The 6 Truths of Organic Chemistry

One of blog writer in "Chemistry Blog" namely Azmanam in his recent blog article entitled "How to Succeed in Organic Chemistry", has listed out some interesting points and called them as 6 truths of Organic chemistry, which every organic chemistry student must remember, are as follows.
1) Approach unknown reactions just like you should approach all reactions
– Identify nucleophile(s)
– Identify electrophile(s)
– Nucleophiles attack electrophiles
– Repeat
2) Weaker Acid Wins
– In and acid/base equilibrium, the equilibrium favors the side of the arrow with the weaker acid (the compound with the higher pKa)
3) Mind your charges
– Make sure the net charge of all compounds is consistent throughout a mechanism
4) The 2nd Best Rule
– The 2nd best resonance structure usually defines a functional group’s reactivity
5) When in doubt: Number Your Carbons!
– When coupling 2 molecules, if it not readily obvious where the various atoms go in the product, number the carbon atoms in the starting material and map those numbers on to the product.
6) Carbonyls: THE CODE
– There are only 3 elementary steps in a carbonyl addition mechanism.
1) Proton Transfer (always reversible)
2) Nucleophilic Addition to a Carbonyl (electrons go up onto oxygen)
3) Electrons Collapse Down from Oxygen (and kick out a good leaving group)

The steps can be in any order and repeated, but those are the only 3 steps needed for addition to acid chlorides, acid anhydrides, aldehydes, ketones, amides, esters, and carboxylic acids (including aldol and Claisen reactions).