Carbonyls and isomers Flashcards
What are the two main types of isomerism?
Structural isomerism and stereoisomerism
What are the three types of structural isomerism?
Chain isomerism, position isomerism, functional group isomerism
What are the two types of stereoisomerism?
Geometric isomerism and optical isomerism
Which organic molecules demonstrate optical isomerism?
Ones containing chiral carbons
How can chiral carbons be identified?
Carbon atoms with four different groups surrounding them
What are enantiomers?
Molecules with the same structural formula but exhibiting optical isomerism
How do enantiomers differ in terms of their mirror images?
They are non-superimposable upon their mirror images
How do enantiomers differ in terms of their effect on plane polarized light?
They rotate it in opposite directions
What is a racemic mixture?
A 50:50 mixture of two enantiomers
Explain the effect of a racemic mixture on plane polarized light
One enantiomer rotates the light clockwise and the other anti-clockwise, resulting in no net rotation.
Which homologous series are considered “carbonyls”?
Aldehydes and ketones
How can aldehydes and ketones be distinguished?
Fehling’s solution or Tollen’s reagent
How can aldehydes be formed?
Oxidation of a primary alcohol or reduction of a carboxylic acid
How can ketones be formed?
Oxidation of a secondary alcohol
Name the reagent and conditions for the reduction of carbonyl compounds
NaBH₄, aqueous
How is the reductant represented in equations?
[H]
What is the name of the mechanism for the reduction of carbonyls?
Nucleophilic addition
Under which conditions are hydroxynitriles formed?
Addition of KCN followed by dilute acid to a carbonyl
Explain how nucleophilic additions of carbonyls with KCN can result in a racemic mixture
Carbonyl is planar, KCN can attack from above or below with equal probability, 50:50 chance of forming each enantiomer
Which hazards are associated with using KCN?
It is highly toxic
