6 truths of organic chemistry

Question 1

1) Approach unknown reactions just like you should approach all reactions

Answer 1

– Identify nucleophile(s)
– Identify electrophile(s)
– Nucleophiles attack electrophiles
– Repeat

Question 2

2) Weaker Acid Wins

Answer 2

– In and acid/base equilibrium, the equilibrium favors the side of the arrow with the weaker acid (the compound with the higher pKa)

Question 3

3) Mind your charges

Answer 3

– Make sure the net charge of all compounds is consistent throughout a mechanism

Question 4

4) The 2nd Best Rule

Answer 4

– The 2nd best resonance structure usually defines a functional group’s reactivity

Question 5

5) When in doubt: Number Your Carbons & draw out hidden hydrogens!

Answer 5

– 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.

-Also, draw out hidden hydrogens at the reaction site

Question 6

6) Carbonyls: THE CODE

Answer 6

– 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 reaction