Advanced Topic 871 of 1102 Organic Chemistry
Sharpless Epoxidation
An enantioselective epoxidation of allylic alcohols using titanium and tartrate.
In-depth explanation of Sharpless Epoxidation
The Sharpless epoxidation converts allylic alcohols into chiral epoxides using titanium tetraisopropoxide, diethyl tartrate and tert-butyl hydroperoxide as the oxidant. The chiral tartrate ligand coordinates the titanium and the allylic alcohol so that the oxygen is delivered to one specific face of the alkene. The choice of the (+) or (-) enantiomer of diethyl tartrate determines which face is epoxidized, so the product's configuration can be predicted. The method gives very high enantiomeric excess and is widely used to make chiral building blocks. Its discoverers shared the 2001 Nobel Prize in Chemistry.
Going deeper: Sharpless Epoxidation
Key ideas: Enantioselective epoxidation of allylic alcohols using titanium tetraisopropoxide, tert-butyl hydroperoxide and diethyl tartrate (DET) as chiral ligand. L-(plus)-DET and D-(minus)-DET deliver oxygen to opposite faces of the alkene, giving predictable epoxide enantiomer with often over 90 percent ee. Molecular sieves keep the system dry. Requires the allylic OH to bind titanium. Nobel Prize 2001 with Noyori and Knowles.
Common mistakes and connections: Students think it works on any alkene; it needs the allylic hydroxyl group. Another error is forgetting the product is a single enantiomer in excess, not a racemate. Links to asymmetric synthesis, epoxides and chiral catalysts.
Worked example and use case
Sharpless epoxidation of an allylic alcohol with the appropriate tartrate gives a single enantiomer of the epoxy alcohol.
Frequently asked questions about Sharpless Epoxidation
What is Sharpless Epoxidation?
An enantioselective epoxidation of allylic alcohols using titanium and tartrate.
Is Sharpless Epoxidation a beginner, intermediate or advanced topic?
Sharpless Epoxidation is a advanced topic in Organic Chemistry. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Sharpless Epoxidation?
Study these earlier topics in Organic Chemistry first: Williamson vs Elimination, Reduction of Carbonyls, Epoxides.
What comes after Sharpless Epoxidation?
The next topics in Organic Chemistry are Hydroboration-Oxidation and Baeyer-Villiger Oxidation.
Can I practise Sharpless Epoxidation with quizzes?
Yes. The interactive lesson includes a self-check question on Sharpless Epoxidation, and the Organic Chemistry quiz draws on every topic in this area.
Where Sharpless Epoxidation fits in Organic Chemistry
Sharpless Epoxidation is topic 143 of 148 in Organic Chemistry.