Assign relative priorities to the groups or atoms in each of...

Assign relative priorities to the groups or atoms in each of the following sets: a. $-\mathrm{CH}_{2} \mathrm{OH}$ $\begin{array}{llll}\text { b. }-\mathrm{CH}_{2} \mathrm{Br} & -\mathrm{OH} & -\mathrm{CH}_{3} & -\mathrm{CH}_{2} \mathrm{OH} \\ \text { c. }-\mathrm{CH}\left(\mathrm{CH}_{3}\right)_{2} & -\mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br} & -\mathrm{CI} & -\mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}\end{array}$

Assign relative priorities to the groups or atoms in each of the following sets:
a. $-\mathrm{CH}_{2} \mathrm{OH}$
$\begin{array}{llll}\text { b. }-\mathrm{CH}_{2} \mathrm{Br} & -\mathrm{OH} & -\mathrm{CH}_{3} & -\mathrm{CH}_{2} \mathrm{OH} \\ \text { c. }-\mathrm{CH}\left(\mathrm{CH}_{3}\right)_{2} & -\mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br} & -\mathrm{CI} & -\mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Br}\end{array}$

Key Concepts

Atomic Number Comparison

A core aspect of the CIP rules is the direct comparison of the atomic numbers of the atoms immediately attached to the stereocenter. Atoms with higher atomic numbers receive higher priority, making this concept crucial for determining the hierarchy of substituents on a molecule.

Substituent Branching and Tie Breaking

When the atoms directly attached to the stereocenter are identical, the next layer of atoms is examined to resolve the priority. This involves considering the atoms attached to the first set of atoms, continuing outward until a difference is found. This stepwise comparison is essential for accurately determining the order of substituents when the immediate atoms do not provide a clear ranking.

Cahn-Ingold-Prelog (CIP) Priority Rules

This set of rules is used to assign priorities to substituents based on their atomic numbers and connectivity. It provides a systematic way to determine stereochemical configurations by comparing the substituents attached to a stereocenter, where the higher the atomic number, the higher the priority. In cases of ambiguity, the rules extend to atoms further away from the reference point.

Treatment of Multiple Bonds

Multiple bonds within substituents are treated as if the atoms are duplicated or triplicated. This approach allows the CIP rules to be applied consistently, as double and triple bonds are expanded into equivalent single-bond systems, facilitating the comparison of groups that include multiple bonds.

Transcript

00:01 Here in question number 19 we have to assign priority numbers how only only by three points we can decide the priority number so first point is atoms with highest atomic number should have highest priority so highest atomic number we have to check atomic number that should have highest priority so highest atomic number we have to check atomic number that should have highest priority priority this is this point we have to we have to consider second point important is to decide the priority in case of ties look at the next atoms along the chain if both are carbon then these carbons are at least to which carbon or which atom which we can decide so we have to check the next number in case of ties next atomic number or next atom third important point is double and triple bonds are treated like bonds to duplicate atoms like if this carbon is having the double bond and this is here then how to assign this we have to consider that this first carbon is attest to two carbon atoms in case of double or triple bonds it should be three carbon atoms so we have to consider this and accordingly we can decide the priority number now come to priority number of the first one a ch2 oh h ch3 h and ch2 ch2 which is given out of this this is hydrogen all three are carbon so next number is here oxygen here hydrogen and here it is again carbon so this should get the highest priority so we can say one here then methyl group in place of methyl group this should get the second priority because carbon is coming here then this should be third priority and this is the fourth one similarly in case of b, first priority should be this one, oh, oxygen highest atomic number out of all this.

03:27 Then all are carbon.

03:29 After that we have to see the next number.

03:32 So br is here...

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