Question

In each reaction box, place the best reagent and conditions from the list below.

In each reaction box, place the best reagent and conditions from the list below. In each reaction box, place the best reagent and conditions from the list below.

Answer 1

Concepts and reason

The problem is solved using the given reagents. These reagents are used for the conversion of one compound to another. Different reagents has different functions and can be used for different conversions. Using suitable reagents, one compound can be converted into a different compound having a different functional group.

The starting compound is an alkyne and the final product is vicinal dihalide. Vicinal dihalides are organic compounds in which two halogen atoms are attached on the adjacent carbon atoms.

Alkenes and alkynes undergo addition reaction in which atoms are added across the multiple bonds and the corresponding saturated compound is formed.

Fundamentals

Addition of halogens occurs in a syn fashion across the double bond. It is known as anti addition. A general reaction is as follows:

Here X is any halogen atom.

Different bond type represents different positions of the groups with respect to the plane of the paper.

1. Solid bond represents the atom that is attached to the bond, which is present in the plane.

2. Dash bond represents the atom that is attached to the bond, which is present below the plane.

3. Wedge bond represents the atom that is attached to the bond, which is above the plane.

The incorrect reagents or the reagents that are not suited for the given conversion reaction are as follows:

1. ${\rm{B}}{{\rm{H}}_{\rm{3}}}{\rm{/THF}}$

2. ${\rm{NaB}}{{\rm{H}}_{\rm{4}}}$

3. ${{\rm{H}}_{\rm{2}}}{\rm{,Lindlar's catalyst}}$

4. ${\rm{PB}}{{\rm{r}}_{\rm{3}}}$

5. ${\rm{C}}{{\rm{H}}_{\rm{3}}}{\rm{Br}}$

6. ${\rm{NaN}}{{\rm{H}}_{\rm{2}}}\left( {{\rm{excess}}} \right)$

7. ${{\rm{H}}_{\rm{2}}}{\rm{,Pt}}$

8. ${\rm{HBr}}$

The given conversion reaction is as follows:

$—C=C— $

The suitable reagents for the given conversion are as follows:

1. ${\rm{Li/N}}{{\rm{H}}_{\rm{3}}}\left( l \right)$

2. 1 equiv. ${\rm{B}}{{\rm{r}}_{\rm{2}}}$

The incorrect reagents or the reagents that are not suited for the given conversion reaction are as follows:

1. ${\rm{B}}{{\rm{H}}_{\rm{3}}}{\rm{/THF}}$

2. ${\rm{NaB}}{{\rm{H}}_{\rm{4}}}$

3. ${{\rm{H}}_{\rm{2}}}{\rm{,Lindlar's catalyst}}$

4. ${\rm{PB}}{{\rm{r}}_{\rm{3}}}$

5. ${\rm{C}}{{\rm{H}}_{\rm{3}}}{\rm{Br}}$

6. ${\rm{NaN}}{{\rm{H}}_{\rm{2}}}\left( {{\rm{excess}}} \right)$

7. ${{\rm{H}}_{\rm{2}}}{\rm{,Pt}}$

8. ${\rm{HBr}}$

The given conversion reaction is as follows:

The suitable reagents for the given conversion are as follows:

1. ${\rm{Na/N}}{{\rm{H}}_{\rm{3}}}\left( l \right)$

2. 1 equiv. ${\rm{B}}{{\rm{r}}_{\rm{2}}}$

Ans: