36. [gr]α-Reactivity and Condensation Reactions
Freshman Organic Chemistry II (CHEM 125B)
As in many synthetic procedures, an important challenge in ketone alkylation is choosing reagents and conditions that allow control of isomerism and of single vs. multiple substitution. [gr]β-Dicarbonyl compounds allow convenient alkylation and preparation of ketones and carboxylic acids. The aldol condensation, in which an [gr]a-position adds to a carbonyl group to generate a [gr]β-hydroxy- or an [gr]α,β-unsaturated carbonyl compound, can be driven to completion by removal of water. The Robinson annulation reaction is an important example of conjugate addition to [gr]α,β-unsaturated carbonyl compounds. [gr]α-Acylation of esters as in the Claisen condensation is a key step in the biosynthesis of fatty acids. Determining the constitutional structure of sugars posed a daunting challenge to early carbohydrate chemists.
00:00 - Chapter 1. The Soxhelet Extractor
08:44 - Chapter 2. Alkylation Regiochemistry
16:35 - Chapter 3. Alkylation of B-Dicarbonyl Compounds
22:12 - Chapter 4. Aldol Condensations
29:41 - Chapter 5. Conjugate Addition and Robinson Annulation
44:17 - Chapter 6. Claisen Condensation and Fatty Acid Biosynthesis
49:36 - Chapter 7. Carbohydrate Structures
Complete course materials are available at the Open Yale Courses website: http://oyc.yale.edu
This course was recorded in Spring 2011.