Oxymercuration–Demercuration: Markovnikov Hydration (No Rearrangements)

Oxymercuration–demercuration hydrates alkenes Markovnikov without carbocation rearrangements. Learn the mercurinium ion mechanism, regiochemistry, and common exam traps.

• Overall transformation: Alkene → Markovnikov alcohol
• Reagents: 1) Hg(OAc)2, H2O (or ROH) 2) NaBH4
• Key intermediate: Mercurinium ion (bridged)
• Regiochemistry: OH ends up on more substituted carbon
• Rearrangements: None (no free carbocation)
• Exam type: Predict the major product
• Exam type: Regiochemistry
• Exam type: Stereochemistry