Question

(R)-Pulegone is converted to \((R)\)-citronellic acid by addition of \(\mathrm{HCl}\) followed by treatment with \(\mathrm{NaOH}\).

Short answer

Question: Describe the major steps taking place in the conversion of (R)-Pulegone to (R)-citronellic acid via addition of HCl and subsequent treatment with NaOH. Answer: The conversion involves two major steps: 1) Addition of HCl to (R)-Pulegone, where a Cl- nucleophile attacks the carbonyl carbon, forming a tetrahedral intermediate which then loses a H+ to form an addition product with a new C-Cl bond and an O-H bond. 2) Treatment with NaOH, in which a hydroxide ion (OH-) attacks the carbon bonded to the chlorine atom, leading to the elimination of a chlorine atom (Cl-) and the formation of a carbon-oxygen double bond.

Step-by-step solution

Addition of HCl to (R)-Pulegone

In this step, hydrochloric acid (HCl) is added to (R)-Pulegone. In this reaction, the nucleophile \(\mathrm{Cl^{-}}\) will attack the carbonyl carbon of the (R)-Pulegone, which will lead to the formation of a tetrahedral intermediate. The intermediate will then lose a \(\mathrm{H^+}\) to form an addition product. The overall process taking place is the formation of a new C-Cl bond and an O-H bond.

Treatment with NaOH

After the addition of HCl, the product formed is treated with sodium hydroxide (NaOH). In this step, a hydroxide ion \(\mathrm{OH^{-}}\) (which is the nucleophile) from NaOH attacks the carbon atom bonded to the chlorine atom formed in the previous step. This leads to the elimination of a chlorine atom as \(\mathrm{Cl^{-}}\) and the formation of a carbon-oxygen double bond. The overall process taking place is the formation of an O-H bond and the loss of a Cl atom as \(\mathrm{Cl^{-}}\). Upon completing these two steps, we have successfully converted (R)-Pulegone into (R)-citronellic acid via addition of HCl and subsequent treatment with NaOH.