Q 25 E - Organic Chemistry (Mcmurry)

Question

Question: Use curved arrows to draw the protonated form of each Lewis base below.

Step-by-Step Solution

Answer

a)

b)

c)

d)

Step 1: Definition of the protonated form

Protonation is the addition of a proton to the molecule, atom, or ion which results in the formation of conjugate acid.

In simple words, Lewis bases abstract the proton and result in the formation of conjugate acid.

Step 2: Reaction of tetrahydrofuran with proton

In this reaction lone pair present on oxygen abstracts, the proton and the conjugate acid of tetrahydrofuran are formed. The reaction is shown as below; 

Step 3: Subpart (b)

Protonation is the addition of a proton to the molecule, atom, or ion which results in the formation of conjugate acid.

In simple words, Lewis bases abstract the proton and result in the formation of conjugate acid.

Step 4: Reaction of the amide with proton

In this lone pair, the nitrogen gets delocalized so that oxygen is getting an extra negative charge so that it can be denoted to abstract hydrogen. The reaction takes place as follows:

Step 5: Subpart (c)

Protonation is the addition of a proton to the molecule, atom, or ion, resulting in the formation of conjugate acid.

In simple words, Lewis bases abstract the proton and result in the formation of conjugate acid.

Step 6: Reaction of pyridine with proton

Pyridine reacts with a proton to form pyridinium ${\mathrm{C}}_5{\mathrm{H}}_5{\mathrm{NH}}^{+}$. In this reaction lone pair of nitrogen abstract proton.

Step 7: Subpart d)

Protonation is the addition of a proton to the molecule, atom, or ion which results in the formation of conjugate acid.

In simple words, Lewis bases abstract the proton and result in the formation of conjugate acid.

Step 8: Reaction of benzaldehyde with proton

Benzaldehyde reacts with a proton to give the following adduct in which lone pair of oxygen abstract proton. The reaction is as follow: