Question

An organic compound ' \(\mathrm{X}\) ' (molecular formula \(\left(\mathrm{C}_{7} \mathrm{H}_{16} \mathrm{O}\right)\) can resolve in enantiomeric forms. A whenevertreated with \(\mathrm{Cu} / 300^{\circ} \mathrm{C}\), product ' \(\mathrm{B}\) ' is obtained which on refluxing with \(\mathrm{NaOD}\) for a long time gives a compound of mol. wt. \(=118 . \mathrm{X}\) is (A) (B) (C) (D)

Short answer

The organic compound X is 2-methylbutan-2-ol.

Step-by-step solution

Identify the organic compound with the given molecular formula and chiral carbon

With the given molecular formula (C7H16O), the compound must have C7 and O1 at the end. As the compound exists in enantiomeric forms, it has at least one chiral carbon. A chiral carbon has four different substituents groups. Considering these constraints, the structure of X should be 2-methylbutan-2-ol. In this compound, one chiral carbon is present. The molecular structure of X is as follows: CH3 | CH3 - C - OH | CH3

Determine the product when the compound is treated with copper at high temperature

When 2-methylbutan-2-ol is treated with \(\mathrm{Cu} / 300^{\circ} \mathrm{C}\), dehydrogenation occurs in the presence of copper, and one of the hydrogen atoms of the hydroxyl group is removed along with the neighboring hydrogen atom (also attached to the chiral carbon). The resulting product is a double bond connecting the chiral carbon to one of the methyl groups. The product B will be 2-methylbut-2-ene: CH3 | CH3 - C = CH2 | CH3

Identify the product after refluxing with NaOD

Finally, 2-methylbut-2-ene is refluxed with sodium deuteroxide (NaOD) for a long time. This reaction is an example of an elimination reaction, where the sodium deuteroxide acts as a strong base, abstracting a hydrogen. The resulting product is an alkene. In this case, a hydrogen atom from the methyl group next to the chiral carbon is removed, and the resulting product is an alkene with a double bond between the two carbons of the chiral carbon's substituents. The final product after refluxing with NaOD is 3-methylhex-1-ene: H2C = CH - CH(CH3) - CH2 - CH2 - CH2 The molecular weight of the final product is 118, which is consistent with what the exercise states. Therefore, X is 2-methylbutan-2-ol.

Key concepts

Enantiomers

Enantiomers are an interesting pair in the world of organic chemistry. They are molecules that are mirror images of each other, much like your left and right hands. However, they cannot be superimposed on each other, which is why they are called chiral or having chirality. Chirality in organic compounds arises when a carbon atom is bonded to four different substituents, creating what is known as a chiral center.
This concept is crucial because enantiomers often display different behaviors when interacting with other chiral molecules, such as enzymes, or in other chiral environments. To make it simpler: imagine a bottle cap that screws onto a bottle; if you have the wrong thread type, it will not fit. That is what chiral specificity means in a molecular sense.

• Enantiomers have identical physical properties like melting point and boiling point, except for how they interact with polarized light.
• They rotate plane-polarized light in different directions, with one rotating it to the right (dextrorotatory) and the other to the left (levorotary).

Enantiomers play a significant role in biochemistry and pharmaceutical industries, where the correct orientation can determine the effectiveness of a drug or interaction in a biological system.

Dehydrogenation

Dehydrogenation is a chemical reaction that involves the removal of hydrogen atoms from an organic molecule. It's mainly used to introduce unsaturation, such as double or triple bonds, into molecules and is a common method in organic synthesis.
In the context of the given exercise, the compound 2-methylbutan-2-ol goes through a dehydrogenation process when treated with copper at a high temperature. Here's how it works:

• The dehydrogenation utilizes a catalyst, like copper, to facilitate the breaking of bonds to remove hydrogen atoms.
• This specific reaction results in the formation of a double bond, turning the alcohol (2-methylbutan-2-ol) into an alkene (2-methylbut-2-ene).

This reaction is important because it transforms the functional group, aiding in the compound's further chemical transformation or reaction.
Dehydrogenation is crucial in the industrial production of alkenes, which are key starting materials for various synthetic pathways.

Elimination Reactions

Elimination reactions are a type of chemical reaction where two substituents are removed from a molecule, forming a double bond. In organic synthesis, these reactions are essential for creating alkenes from alcohols or alkyl halides. The key feature of elimination reactions is that they change the saturation of the molecule. During the exercise, after the formation of 2-methylbut-2-ene through dehydrogenation, the compound undergoes another transformation when reacted with sodium deuteroxide (NaOD).
This process involves:

• The elimination of a hydrogen atom adjacent to the chiral center, creating a new alkene with a shifted double bond.
• It's another example of an elimination reaction that promotes further saturation change, resulting in 3-methylhex-1-ene.

Elimination reactions like this are not only important for adjusting molecular structure but are also pivotal in organic synthesis to develop new compounds with desired properties. They are common in creating molecules with potential applications in pharmaceuticals and advanced materials.