Isomerism

Draw the structure of (E)-1-bromo-1-chloropropene

what two features must a molecule have to show E/Z isomerism?

restricted rotation around the carbon double bond

2 different functional groups attached to each carbon in the carbon double bond

how do you identify the higher priority groups in an E/Z isomer?

priority is based on the higher atomic number

define optical isomers

non-superimposable mirror images

what is another word for optical isomer?

enantiomer

What are the features of a molecule with optical isomers

have a chiral carbon center with 4 different functional groups attached

How do you show which carbon is the chiral center in a structural formula?

add an Asterix *

draw the basic structure of all optical isomers, and state the shape and bond angles

tetra hedral

bond angles of 109.5

draw out the displayed formula of 2-methylbutanoic acid and identify the chiral carbon

Pentan-2-one and pentan-3-one can both be converted into secondary alcohols, the alcohols produced do not rotate plane polarised light explain this observation (4 marks)

pentan-3-one produces a racemic mixture. As the molecule is planar around the carbonyl group. There is an equal chance for nucleophilic attack above or below the plane.

the products of pentan-2-one do not produce chiral carbons, no optical isomers produced.