Q.3 - Organic Chemistry

Question

For which double bonds are stereoisomers possible?

a.

b.

c.

Step-by-Step Solution

Answer

The stereoisomers possible for double bonds are present in:

But is not possible for: 

Definition of stereoisomers

Stereoisomers isomers are those kinds of isomers where the molecular formula and structures remain the same, and the spatial arrangement of atoms is different.

Cis/Z and trans/E are the two kinds of stereoisomers. Stereoisomer is possible in those structures where different substituents are present across the double-bonded carbons.

Identification of the double bond

The double-bonded carbons are identified first and are marked as blue.

Representation of double bonds in the structures

Finding of stereoisomers

a.

 Compound a

A stereoisomer is not possible here since two similar alkyl groups are attached to the same carbon.

 

b. 

Compound b

Stereoisomer is possible here since different alkyl groups are present in the double-bonded carbon. The alkene here is considered to be trans/E.

c.

Compound c

Similar to b, here, stereoisomer is possible because different alkyl groups are present in the double-bonded carbon. The alkene here is considered to be trans/E.

 

Thus, the stereoisomers possible for double bonds are present in compounds b and c.