Fundamentals of Organic ChemistryChemistryHaloalkanes and Haloarenes
Consider the following reaction sequence: Identify the correct statement regarding the products A and B .
Options
- AB is optically inactive due to external compensation.
- BB does not have any chiral centres.
- CB is optically inactive due to internal compensation.
- DA is predominantly a cis -alkene.
Correct answer
A. B is optically inactive due to external compensation.
Step-by-step solution
The given starting material is meso-2,3-dibromobutane. Reaction with NaI in acetone causes the dehalogenation of the vicinal dibromide. This reaction proceeds via an anti-elimination mechanism. Anti-elimination of the meso isomer yields the trans-alkene. Thus, product A is trans-2-butene. Next, trans-2-butene reacts with trifluoroperacetic acid ( CF₃CO₃H ). Peroxyacids undergo a concerted syn-addition to alkenes to form epoxides. Syn-addition of an oxygen atom to trans-2-butene yields trans-2,3-dimethyloxirane as p