Consider the following reaction The number of stereoisomer(s) formed during this reaction will be
Show Hint
Always check if the product can have a meso form. In this case, since the groups at C1 (Cl, Me) and C2 (H, Me) are different, no internal plane of symmetry exists, so there are no meso compounds.
Step 1: Understanding the Concept:
Electrophilic addition of HCl to an alkene proceeds via a carbocation intermediate, following Markovnikov's rule. Step 2: Detailed Explanation:
1. Mechanism: Protonation of the double bond gives a stable tertiary carbocation at one of the ring carbons.
2. Product: Chloride ion then attacks the carbocation, yielding 1-chloro-1,2-dimethylcyclopentane.
3. Stereocenters: The product has two chiral carbons: C1 (bonded to Cl, Me, C2, C5) and C2 (bonded to H, Me, C1, C3).
4. Counting Isomers: With 2 chiral centers and no plane of symmetry (due to Cl vs H at the two sites), the total number of stereoisomers is \(2^n = 2^2 = 4\). These comprise two pairs of enantiomers (RR/SS and RS/SR). Step 3: Final Answer:
The number of stereoisomers formed is 4.
