tical Isomerism
a form of stereoisomerism have same structural formula but different
arrangement of atoms in space
optical isomers are mirror images of each other
non superimposable no matter which wayyou turn them they will not
er lap
optical isomers have a chiral carbon atom
chiral molecule has a different groups attached to a carbonatom
can arrangethesegroups in 2different ways which forms 2different
olecules we call these enantiomers
drawing enantiomers
find chiral centre fromdisplayed formula and draw them in a tetrahedral
shape then draw mirror image to show both enantiomers
Plane polarised light
chiral molecules are optically active
opticallyactive isomers will rotate planepolarisedlight oneenantiome
ill will rotate lightclockwiseand the other anticlockwise but degrees of
otation is the same
standard light oscillates in all directions pass this through a polaroid
it er only allows one orientation to passso light oscillates in onedirection
nd producesplanepolarised light
Racemates
when we have an equal amount of each enantiomer we have a racemic
ixture
race mates do not rotate plane polarised the 2 enantiomers rotate light
oppositedirections by the same degrees so they cancel out
racemicmixtures of a chiral productoften made byreactingachiral substance
uneven chance offormingeach enantiomer
egl types of enantiomers
Br t
s iight Ie pier or a
gig Her
either of the hydrogen atoms can be replacedproducing a mixture
f enantiomers 50150 chance of either hydrogenbeingreplaced so the
z
omers are made in equal quantities
difficult to adapt a reaction to onlyproduce 1 enantiomers can be
may beneeded if one of the expensive
enantiomers is dangerous life threatening
molecules with planar profiles such as double bonds in C C and C o can mak
acemicproducts
these reactions occur when we have an attack on the carbonylgroup c o
f unsymmetrical ketones and aldehydes
nucleophile can attack either from above or belowforming2different
nantiomers seven chance of attack from topand bottom
type of enantiomer formed will depend on if the nucleophile attacks
rom the top or bottom
a form of stereoisomerism have same structural formula but different
arrangement of atoms in space
optical isomers are mirror images of each other
non superimposable no matter which wayyou turn them they will not
er lap
optical isomers have a chiral carbon atom
chiral molecule has a different groups attached to a carbonatom
can arrangethesegroups in 2different ways which forms 2different
olecules we call these enantiomers
drawing enantiomers
find chiral centre fromdisplayed formula and draw them in a tetrahedral
shape then draw mirror image to show both enantiomers
Plane polarised light
chiral molecules are optically active
opticallyactive isomers will rotate planepolarisedlight oneenantiome
ill will rotate lightclockwiseand the other anticlockwise but degrees of
otation is the same
standard light oscillates in all directions pass this through a polaroid
it er only allows one orientation to passso light oscillates in onedirection
nd producesplanepolarised light
Racemates
when we have an equal amount of each enantiomer we have a racemic
ixture
race mates do not rotate plane polarised the 2 enantiomers rotate light
oppositedirections by the same degrees so they cancel out
racemicmixtures of a chiral productoften made byreactingachiral substance
uneven chance offormingeach enantiomer
egl types of enantiomers
Br t
s iight Ie pier or a
gig Her
either of the hydrogen atoms can be replacedproducing a mixture
f enantiomers 50150 chance of either hydrogenbeingreplaced so the
z
omers are made in equal quantities
difficult to adapt a reaction to onlyproduce 1 enantiomers can be
may beneeded if one of the expensive
enantiomers is dangerous life threatening
molecules with planar profiles such as double bonds in C C and C o can mak
acemicproducts
these reactions occur when we have an attack on the carbonylgroup c o
f unsymmetrical ketones and aldehydes
nucleophile can attack either from above or belowforming2different
nantiomers seven chance of attack from topand bottom
type of enantiomer formed will depend on if the nucleophile attacks
rom the top or bottom
