Question

Which of the following is the best reaction sequence to use if one wants to accomplish a Markovnikov addition of water to an alkene with minimal skeletal rearrangement?

A) water + dilute acid
B) water + concentrated acid
C) oxymercuration-demercuration
D) hydroboration-oxidation
E) none of the above

Answer 1

Oxymercuration-demercuration is the best method for Markovnikov addition of water to an alkene as it minimizes skeletal rearrangement by avoiding carbocation formation.

Step-by-step explanation:

To achieve a Markovnikov addition of water to an alkene with minimal skeletal rearrangement, the best reaction sequence would be oxymercuration-demercuration. Option A, water plus dilute acid, and B, water plus concentrated acid, are traditional acid-catalyzed hydration methods that can potentially lead to carbocation rearrangements, thus are not the best choices.

Option D, hydroboration-oxidation, results in anti-Markovnikov addition, so it is not suitable for achieving Markovnikov selectivity. On the other hand, the oxymercuration-demercuration process utilizes mercuric acetate and water, followed by reduction with sodium borohydride, which avoids carbocation formation and thus minimizes the risk of rearrangement.