Chapter 12 Aldehydes and Ketones Irene Lee Case Western Reserve University Cleveland, OH ©2004, Prentice Hall

Nomenclature of Aldehydes

Nomenclature of Ketones

An aldehyde has a greater partial positive charge on its carbonyl carbon than does a ketone

The carbonyl carbon of an aldehyde is more accessible to the nucleophile Ketones have greater steric crowding in their transition states, so they have less stable transition states Steric factors contribute to the reactivity of an aldehyde

Formation of a New Carbon–Carbon Bond Using Grignard Reagents Grignard reagents react with aldehydes, ketones, and carboxylic acid derivatives 格林试剂

亲核加成反应机理

Aldehydes and ketones react with nucleophiles to form addition products: nucleophile addition reactions Nu - ： 亲核加成反应机理

Reaction with Acetylide Ions

Synthesis Using Cyanohydrin

Hydride addition Functional group transformation :H –

Utilization of DIBAL to Control the Reduction Reaction

Imine formation a Schiff base

The keto group is protected as a ketal in this synthesis

Enolates lithium diisopropylamide LDA LDA is a bulky molecule and this prevents it attacking the carbonyl group in a nucleophilic substitution reaction.

Alkylations