Geometric Isomerism

1
Geometric Isomerism
R W Grime Ripon Grammar School
2
(No Transcript)
3
(No Transcript)
4
GEOMETRIC ISOMERISM
X
CANNOT ROTATE AROUND CC
5
GEOMETRIC ISOMERISM
(E) but-2-ene
(Z) but-2-ene
E entgegen (opposite)
Z zusammen (together)
6
GEOMETRIC ISOMERISM
PRIORITY H lt CH3 lt CH2CH3 Look at atomic
numbers of atoms attached to CC (or subsequent
atoms if the same). Highest values opposite
E Highest values together Z
Z 2-bromo-2-fluorobut-2-ene
E 3-methylpent-2-ene
7
GEOMETRIC ISOMERISM
trans but-2-ene (E) but-2-ene
cis but-2-ene (Z) but-2-ene
BOTH C ATOMS OF CC MUST HAVE TWO DIFFERENT
GROUPS
8
TASK
NO
methylpropene
YES
E
Z
1-chloropropene
9
TASK
NO
2-methylpent-2-ene
NO
2-ethylpent-1-ene
10
TASK
YES
E
Z
3-methylpent-2-ene
NO
but-1-ene
11
TASK
YES
Z
E
3,4-dimethylhex-3-ene
YES
E
Z
2-bromo-3-chlorobut-2-ene