Now that we know about various electronic effects, let’s learn the Intermediates found in organic chemistry reactions.
For this we must understand the difference between reaction intermediate and transition state.
Starting with carbon intermediates, carbocation is the first one:
Answer is that: carbon when loses its shared pair of electrons (to Z as Z-) it only gives one electron to Z and hence Single + charge.
Similarly, if bonded pair is taken by carbon relieving a positive ion, a carbanion is formed.
When the shared pair is equally cleaved giving one electron to carbon, a free radical is formed.Two more intermediates:
Let’s start with Carbocation, structure, generation and stability:
For carbanions and free radicals:
Let’s now go through carbenes (video below at 48:44 min):
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Here we would know about the various effects due to the bonded pairs in organic molecules.
Types of electronic effects we would deal with are:
Various types of reactions in organic chemistry are also introduced here:
Amino Acids Synthesis
The slides explained in the video are:
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Amino acids: Structure and classification, stereochemistry and their acid base behaviour
The slides explained in the video are given below:
We shall now move on the internal aspects of Optical isomerism. Before proceeding we must understand and learn to view molecules in 3-D space. For this, one needs to know the different Projection formulae (representation of 3-D structures on a 2-D surface like paper or board).
These are of many types:
Let’s learn them one by one.
When rotated this may be converted to:
Fischer Projection Formulae
This is the best followed convention for representing 3-D structures in 2-D.
However, few rules are to be followed:
(* to get the answer to Why??? please see video @27:18 min. – 32:44 min.)
Although the remaining two types Newmann Projection and Sawhorse Projection formula are mainly used for Conformation analysis but we need these for making Fischer formula of two chiral center systems.
Finally the last concept of racemic mixture: