Chad covers the Hydration of Alkynes in this lesson. He begins with a review of the three alkene hydration reactions: 1) acid-catalyzed hydration (Markovnikov), 2) oxymercuration-demercuration (Markovnikov), and 3) hydroboration-oxidation (anti-Markovnikov). He then relates to these three alkene reactions the two alkyne hydration reactions: 1) acid-catalyzed hydration of alkynes (Markovnikov) and 2) hydroboration-oxidation of alkynes (anti-Markovnikov). He shows that the addition of one equivalent of H2O across the alkyne results in an enol which tautomerizes to either a ketone or an aldehyde. He also shows that it is common with alkynes to use a bulky borane for hydroboration oxidation such as disiamylborane (Sia2BH) or dicyclohexylborane. Chad concludes the lesson by showing the mechanisms for Keto-Enol Tautomerization, both acid-catalyzed and base-catalyzed which commonly appear on undergraduate exams covering the alkyne material.

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00:00 Lesson Introduction
00:33 Review of the Hydration of Alkenes
01:40 Acid-Catalyzed Hydration of Alkynes (Markovnikov)
05:56 Hydroboration-Oxidation of Alkynes with disiamylborane (anti-Markovnikov)
09:36 Hydration of Internal Alkynes
11:33 Keto-Enol Tautomerization
13:22 Keto-Enol Tautomerization Mechanism (Acid-Catalyzed)
14:37 Keto-Enol Tautomerization Mechanism (Base-Catalyzed)

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