4.1.3 Alkenes: stereoisomerism

Question 1

what are stereoisomers?

Answer 1

compounds with the same structural formula but with a different arrangement in space

Question 2

what is E-Z isomerism?

Answer 2

a type of stereoisomers which occurs due to the limited rotation around a double carbon bond (requirement for two different groups to be attached to each C atom of the double CC atom

Question 3

what does high priority mean in relation to E/Z isomerism?

Answer 3

high priority- the one with highest Mr (if same, then surrounding atoms)

Question 4

what happens in E-Z isomerism?

Answer 4

the limited rotation means that ‘high priority’ groups attached to the carbon carbon double bond can be either ‘together’ or ‘opposite’

Question 5

which is an E isomer?

Answer 5

think the cc double bond is train tracks, when the high priority groups are on opposite sides of the train tracks

Question 6

which is a Z isomer?

Answer 6

zusammen=together
think the cc double bond is train tracks, when the high priority groups are on the same side of the train tracks

Question 7

nemonic

Answer 7

cisters are on zee zame zide

Question 8

what is cis trans isomerism?

Answer 8

a special case of E/Z isomerism in which two of the substituent groups attached to each carbon atom of the cc double group are the same

Question 9

cis is used instead of

Answer 9

Z

Question 10

trans is used instead of

Answer 10

E

Question 11

how is the Cahn-Ingold-Preolog priority rule used?

Answer 11

used to identify the priority in E/Z stereoisomers (the atom or group on either side of cc double bond with the highest Mr has higher priority