Lecture 15 - Metals and Catalysis in Alkene Oxidation, Hydrogenation, Metathesis, and Polymerization. Alkenes may be oxidized to diols by permanganate or by OsO4 catalysis. Metal catalysts provide orbitals
that allow simultaneous formation of two bonds from metal to alkene or H2. Coupling such oxidative additions to reductive eliminations, provides a low-energy catalytic path for addition of H2 to an alkene.
Such catalytic hydrogenation is often said to involve syn stereochemistry, but the primary literature shows that addition can be anti when allylic rearrangement occurs on the catalyst. Similar oxidative/reductive cycles operate
in olefin metathesis and metal-catalyzed polymerization. Careful catalyst design allows control over polymer stereochemistry (tacticity). Polymerizations catalyzed by free-radicals or acids typically lack stereochemical control,
but there are ways to control regiochemistry and chain length. Latex, a natural polymer, coagulates to form a rubber ball.
(from oyc.yale.edu)
Lecture 15 - Metals and Catalysis in Alkene Oxidation, Hydrogenation, Metathesis
Time
Lecture Chapters
[00:00:00]
1. Alkene Dihydroxylation
[00:04:28]
2. Catalytic Hydrogenation of Alkenes: Oxidative Addition, Reductive Elimination
[00:15:08]
3. Catalytic Hydrogenation of Alkenes: Stereochemistry
[00:25:50]
4. Olefin Metathesis, Polymerization, and Tacticity
[00:39:00]
5. Radical Polymerization
[00:43:16]
6. Electrophilic Oligomerization and Polymerization and Rubber